psa: wrapper: Fix potential unreachable statement warning

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/library/psa_crypto_driver_wrappers.c b/library/psa_crypto_driver_wrappers.c
index 765920f..32c957e 100644
--- a/library/psa_crypto_driver_wrappers.c
+++ b/library/psa_crypto_driver_wrappers.c
@@ -751,7 +751,8 @@
             if( status == PSA_SUCCESS )
                 operation->id = PSA_CRYPTO_MBED_TLS_DRIVER_ID;
 
-            return( status );
+            if( status != PSA_ERROR_NOT_SUPPORTED )
+                return( status );
 #endif /* MBEDTLS_PSA_BUILTIN_CIPHER */
             return( PSA_ERROR_NOT_SUPPORTED );