Remove salt from asymmetric_{sign,verify}

No common signature algorithm uses a salt (RSA-PKCS#1v1.5, RSA-PSS,
DSA, ECDSA, EdDSA). We don't even take an IV for MAC whereas MAC
algorithms with IV are uncommon but heard of. So remove the salt
parameter from psa_asymmetric_sign and psa_asymmetric_verify.
diff --git a/include/psa/crypto.h b/include/psa/crypto.h
index 8ac817a..68e3b0a 100644
--- a/include/psa/crypto.h
+++ b/include/psa/crypto.h
@@ -2241,15 +2241,6 @@
  *                              the type of \p key.
  * \param[in] hash              The hash or message to sign.
  * \param hash_length           Size of the \p hash buffer in bytes.
- * \param[in] salt              A salt or label, if supported by the
- *                              signature algorithm.
- *                              If the signature algorithm does not support
- *                              a salt, pass \c NULL.
- *                              If the signature algorithm supports an
- *                              optional salt and you do not want to pass
- *                              a salt, pass \c NULL.
- * \param salt_length           Size of the \p salt buffer in bytes.
- *                              If \p salt is \c NULL, pass 0.
  * \param[out] signature        Buffer where the signature is to be written.
  * \param signature_size        Size of the \p signature buffer in bytes.
  * \param[out] signature_length On success, the number of bytes
@@ -2274,8 +2265,6 @@
                                  psa_algorithm_t alg,
                                  const uint8_t *hash,
                                  size_t hash_length,
-                                 const uint8_t *salt,
-                                 size_t salt_length,
                                  uint8_t *signature,
                                  size_t signature_size,
                                  size_t *signature_length);
@@ -2296,15 +2285,6 @@
  * \param[in] hash          The hash or message whose signature is to be
  *                          verified.
  * \param hash_length       Size of the \p hash buffer in bytes.
- * \param[in] salt          A salt or label, if supported by the signature
- *                          algorithm.
- *                          If the signature algorithm does not support a
- *                          salt, pass \c NULL.
- *                          If the signature algorithm supports an optional
- *                          salt and you do not want to pass a salt,
- *                          pass \c NULL.
- * \param salt_length       Size of the \p salt buffer in bytes.
- *                          If \p salt is \c NULL, pass 0.
  * \param[in] signature     Buffer containing the signature to verify.
  * \param signature_length  Size of the \p signature buffer in bytes.
  *
@@ -2324,8 +2304,6 @@
                                    psa_algorithm_t alg,
                                    const uint8_t *hash,
                                    size_t hash_length,
-                                   const uint8_t *salt,
-                                   size_t salt_length,
                                    const uint8_t *signature,
                                    size_t signature_length);
 
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index eb140ea..9988ec0 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -1983,8 +1983,6 @@
                                   psa_algorithm_t alg,
                                   const uint8_t *hash,
                                   size_t hash_length,
-                                  const uint8_t *salt,
-                                  size_t salt_length,
                                   uint8_t *signature,
                                   size_t signature_size,
                                   size_t *signature_length )
@@ -1994,9 +1992,6 @@
 
     *signature_length = signature_size;
 
-    (void) salt;
-    (void) salt_length;
-
     status = psa_get_key_from_slot( key, &slot, PSA_KEY_USAGE_SIGN, alg );
     if( status != PSA_SUCCESS )
         goto exit;
@@ -2058,17 +2053,12 @@
                                     psa_algorithm_t alg,
                                     const uint8_t *hash,
                                     size_t hash_length,
-                                    const uint8_t *salt,
-                                    size_t salt_length,
                                     const uint8_t *signature,
                                     size_t signature_length )
 {
     key_slot_t *slot;
     psa_status_t status;
 
-    (void) salt;
-    (void) salt_length;
-
     status = psa_get_key_from_slot( key, &slot, PSA_KEY_USAGE_VERIFY, alg );
     if( status != PSA_SUCCESS )
         return( status );
diff --git a/tests/suites/test_suite_psa_crypto.function b/tests/suites/test_suite_psa_crypto.function
index cbb3f37..9505ab6 100644
--- a/tests/suites/test_suite_psa_crypto.function
+++ b/tests/suites/test_suite_psa_crypto.function
@@ -294,7 +294,6 @@
     {
         TEST_ASSERT( psa_asymmetric_sign( key, alg,
                                           payload, payload_length,
-                                          NULL, 0,
                                           signature, sizeof( signature ),
                                           &signature_length ) == PSA_SUCCESS );
     }
@@ -307,7 +306,6 @@
               PSA_ERROR_INVALID_SIGNATURE );
         TEST_ASSERT( psa_asymmetric_verify( key, alg,
                                             payload, payload_length,
-                                            NULL, 0,
                                             signature, signature_length ) ==
                      verify_status );
     }
@@ -965,7 +963,6 @@
 
     status = psa_asymmetric_sign( key_slot, exercise_alg,
                                   payload, payload_length,
-                                  NULL, 0,
                                   signature, sizeof( signature ),
                                   &signature_length );
     if( policy_alg == exercise_alg &&
@@ -977,7 +974,6 @@
     memset( signature, 0, sizeof( signature ) );
     status = psa_asymmetric_verify( key_slot, exercise_alg,
                                     payload, payload_length,
-                                    NULL, 0,
                                     signature, sizeof( signature ) );
     if( policy_alg == exercise_alg &&
         ( policy_usage & PSA_KEY_USAGE_VERIFY ) != 0 )
@@ -2011,7 +2007,6 @@
     /* Perform the signature. */
     TEST_ASSERT( psa_asymmetric_sign( slot, alg,
                                       input_data->x, input_data->len,
-                                      NULL, 0,
                                       signature, signature_size,
                                       &signature_length ) == PSA_SUCCESS );
     /* Verify that the signature is what is expected. */
@@ -2061,7 +2056,6 @@
 
     actual_status = psa_asymmetric_sign( slot, alg,
                                          input_data->x, input_data->len,
-                                         NULL, 0,
                                          signature, signature_size,
                                          &signature_length );
     TEST_ASSERT( actual_status == expected_status );
@@ -2118,7 +2112,6 @@
     /* Perform the signature. */
     TEST_ASSERT( psa_asymmetric_sign( slot, alg,
                                       input_data->x, input_data->len,
-                                      NULL, 0,
                                       signature, signature_size,
                                       &signature_length ) == PSA_SUCCESS );
     /* Check that the signature length looks sensible. */
@@ -2129,7 +2122,6 @@
     TEST_ASSERT( psa_asymmetric_verify(
                      slot, alg,
                      input_data->x, input_data->len,
-                     NULL, 0,
                      signature, signature_length ) == PSA_SUCCESS );
 
     if( input_data->len != 0 )
@@ -2141,7 +2133,6 @@
         TEST_ASSERT( psa_asymmetric_verify(
                          slot, alg,
                          input_data->x, input_data->len,
-                         NULL, 0,
                          signature,
                          signature_length ) == PSA_ERROR_INVALID_SIGNATURE );
     }
@@ -2184,7 +2175,6 @@
 
     TEST_ASSERT( psa_asymmetric_verify( slot, alg,
                                         hash_data->x, hash_data->len,
-                                        NULL, 0,
                                         signature_data->x,
                                         signature_data->len ) == PSA_SUCCESS );
 exit:
@@ -2225,7 +2215,6 @@
 
     actual_status = psa_asymmetric_verify( slot, alg,
                                            hash_data->x, hash_data->len,
-                                           NULL, 0,
                                            signature_data->x,
                                            signature_data->len );