Wipe sensitive data in psa_mac_verify_finish

Wipe the whole MAC intermediate buffer, not just the requested MAC
size. With truncated MAC algorithms, the requested MAC size may be
smaller than what is written to the intermediate buffer.

library/psa_crypto.c

@@ -1827,7 +1827,7 @@ cleanup:
     else
         psa_mac_abort( operation );
 
-    mbedtls_zeroize( actual_mac, mac_length );
+    mbedtls_zeroize( actual_mac, sizeof( actual_mac ) );
 
     return( status );
 }