Fix mbedtls_svc_key_id_is_null when KEY_ID_ENCODES_OWNER

A null key id is a null key id even when it has an owner attached to it.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/include/psa/crypto_values.h b/include/psa/crypto_values.h
index 6d07533..57ab4c5 100644
--- a/include/psa/crypto_values.h
+++ b/include/psa/crypto_values.h
@@ -2160,7 +2160,7 @@
  */
 static inline int mbedtls_svc_key_id_is_null( mbedtls_svc_key_id_t key )
 {
-    return( ( key.MBEDTLS_PRIVATE(key_id) == 0 ) && ( key.MBEDTLS_PRIVATE(owner) == 0 ) );
+    return( key.MBEDTLS_PRIVATE(key_id) == 0 );
 }
 
 #endif /* !MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER */