Implement, plug in and test validate_key driver entry point

Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>
diff --git a/tests/include/test/drivers/keygen.h b/tests/include/test/drivers/keygen.h
index b72c65c..e5a5e47 100644
--- a/tests/include/test/drivers/keygen.h
+++ b/tests/include/test/drivers/keygen.h
@@ -1,5 +1,5 @@
 /*
- * Test driver for generating keys.
+ * Test driver for generating and verifying keys.
  */
 /*  Copyright The Mbed TLS Contributors
  *  SPDX-License-Identifier: Apache-2.0
@@ -57,5 +57,10 @@
     const psa_key_attributes_t *attributes,
     uint8_t *key, size_t key_size, size_t *key_length );
 
+psa_status_t test_transparent_validate_key(const psa_key_attributes_t *attributes,
+                                           const uint8_t *data,
+                                           size_t data_length,
+                                           size_t *bits);
+
 #endif /* PSA_CRYPTO_DRIVER_TEST */
 #endif /* PSA_CRYPTO_TEST_DRIVERS_KEYGEN_H */