Add signature length mismatch handling when using PSA in pk_verify_ext

Introduce a regression test for that too.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/tests/suites/test_suite_pk.function b/tests/suites/test_suite_pk.function
index d5c7d08..29f8622 100644
--- a/tests/suites/test_suite_pk.function
+++ b/tests/suites/test_suite_pk.function
@@ -429,7 +429,8 @@
                                  int mod, int radix_N, char * input_N,
                                  int radix_E, char * input_E,
                                  data_t * result_str, int pk_type,
-                                 int mgf1_hash_id, int salt_len, int result )
+                                 int mgf1_hash_id, int salt_len, int sig_len,
+                                 int result )
 {
     unsigned char hash_result[MBEDTLS_MD_MAX_SIZE];
     mbedtls_rsa_context *rsa;
@@ -478,7 +479,7 @@
 
     TEST_ASSERT( mbedtls_pk_verify_ext( pk_type, options, &pk,
                                 digest, hash_result, hash_len,
-                                result_str->x, mbedtls_pk_get_len( &pk ) ) == result );
+                                result_str->x, sig_len ) == result );
 
 exit:
     mbedtls_pk_free( &pk );