Implement, plug in and test validate_key driver entry point

Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>
diff --git a/library/psa_crypto_driver_wrappers.h b/library/psa_crypto_driver_wrappers.h
index 0db15d6..b0b483b 100644
--- a/library/psa_crypto_driver_wrappers.h
+++ b/library/psa_crypto_driver_wrappers.h
@@ -43,9 +43,18 @@
                                              const uint8_t *signature,
                                              size_t signature_length );
 
+/*
+ * Key handling functions
+ */
+
 psa_status_t psa_driver_wrapper_generate_key( const psa_key_attributes_t *attributes,
                                               psa_key_slot_t *slot );
 
+psa_status_t psa_driver_wrapper_validate_key( const psa_key_attributes_t *attributes,
+                                              const uint8_t *data,
+                                              size_t data_length,
+                                              size_t *bits );
+
 /*
  * Cipher functions
  */