Add static internal MAC finish function

add new psa_mac_finish_internal() to be called by psa_mac_finish() and
psa_mac_verify() in order to be able to check key usage separatly.
diff --git a/tests/suites/test_suite_psa_crypto.function b/tests/suites/test_suite_psa_crypto.function
index b0cfe20..bda2e7c 100644
--- a/tests/suites/test_suite_psa_crypto.function
+++ b/tests/suites/test_suite_psa_crypto.function
@@ -221,6 +221,7 @@
     unsigned char *expected_mac = NULL;
     size_t expected_mac_size;
     psa_mac_operation_t operation;
+    psa_key_policy_t policy;
 
     key = unhexify_alloc( key_hex, &key_size );
     TEST_ASSERT( key != NULL );
@@ -236,6 +237,12 @@
 
     TEST_ASSERT( psa_crypto_init( ) == PSA_SUCCESS );
 
+    psa_key_policy_init( &policy );
+
+    psa_key_policy_set_usage( &policy, PSA_KEY_USAGE_VERIFY, alg_arg );
+
+    TEST_ASSERT( psa_set_key_policy( key_slot, &policy ) == PSA_SUCCESS );
+
     TEST_ASSERT( psa_import_key( key_slot, key_type,
                                  key, key_size ) == PSA_SUCCESS );
     // TODO: support IV
@@ -427,7 +434,6 @@
 void key_policy_fail( int usage_arg, int alg_arg, int expected_status, char *key_hex )
 {
     int key_slot = 1;
-    psa_key_type_t key_type = PSA_KEY_TYPE_AES;
     unsigned char key[32] = {0};
     unsigned char* keypair = NULL;
     size_t key_size = 0;
@@ -445,27 +451,22 @@
 
     TEST_ASSERT( psa_set_key_policy( key_slot, &policy ) == PSA_SUCCESS );
 
-    switch( usage_arg )
+    if( usage_arg & PSA_KEY_USAGE_EXPORT )
     {
-        case PSA_KEY_USAGE_EXPORT:
-            keypair = unhexify_alloc( key_hex, &key_size );
-            TEST_ASSERT( keypair != NULL );
-            key_type = PSA_KEY_TYPE_RSA_KEYPAIR;
-            TEST_ASSERT( psa_import_key( key_slot, key_type,
-                                 keypair, key_size ) == PSA_SUCCESS );
-            actual_status = psa_asymmetric_sign( key_slot, 
-                            ( psa_algorithm_t )alg_arg, NULL, 0, NULL, 0, 
-                            NULL, 0, &signature_length );
-            break;
-        
-        case PSA_KEY_USAGE_SIGN:
-            key_type = PSA_KEY_TYPE_AES;
-            TEST_ASSERT( psa_import_key( key_slot, key_type,
-                                 key, sizeof( key ) ) == PSA_SUCCESS );
-            actual_status = psa_export_key( key_slot, NULL, 0, NULL );
-            break;
-        default:
-            break;
+        keypair = unhexify_alloc( key_hex, &key_size );
+        TEST_ASSERT( keypair != NULL );
+        TEST_ASSERT( psa_import_key( key_slot, PSA_KEY_TYPE_RSA_KEYPAIR,
+                                keypair, key_size ) == PSA_SUCCESS );
+        actual_status = psa_asymmetric_sign( key_slot, 
+                        ( psa_algorithm_t )alg_arg, NULL, 0, NULL, 0, 
+                        NULL, 0, &signature_length );
+    }
+    
+    if( usage_arg & PSA_KEY_USAGE_SIGN )
+    {
+        TEST_ASSERT( psa_import_key( key_slot, PSA_KEY_TYPE_RSA_KEYPAIR,
+                                key, sizeof( key ) ) == PSA_SUCCESS );
+        actual_status = psa_export_key( key_slot, NULL, 0, NULL );
     }
 
     TEST_ASSERT( actual_status == expected_status );