Add missing zeroize for sensitive tag data.

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
diff --git a/library/psa_crypto_driver_wrappers.c b/library/psa_crypto_driver_wrappers.c
index 1dd3b2d..5e7eb11 100644
--- a/library/psa_crypto_driver_wrappers.c
+++ b/library/psa_crypto_driver_wrappers.c
@@ -1760,6 +1760,8 @@
                         status = PSA_ERROR_INVALID_SIGNATURE;
                 }
 
+                mbedtls_platform_zeroize( check_tag, sizeof( check_tag ) );
+
                 return( status );
             }