Fixed -Wunused warnings when building without asymmetric crypto
diff --git a/include/mbedtls/psa_util.h b/include/mbedtls/psa_util.h
index 8d18fcc..a87ca81 100644
--- a/include/mbedtls/psa_util.h
+++ b/include/mbedtls/psa_util.h
@@ -230,9 +230,11 @@
             *oid_len = MBEDTLS_OID_SIZE( MBEDTLS_OID_EC_GRP_BP512R1 );
             return( 0 );
 #endif /* MBEDTLS_ECP_DP_BP512R1_ENABLED */
+        default:
+            (void) oid;
+            (void) oid_len;
+            return( -1 );
     }
-
-     return( -1 );
 }
 
 #define MBEDTLS_PSA_MAX_EC_PUBKEY_LENGTH 1