spi: don't open code list_for_each_entry_safe_reverse()

The loop declaration in function spi_res_release() can be simplified
by reusing the common list_for_each_entry_safe_reverse() helper
macro.
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi.c

@@ -2721,12 +2721,9 @@ EXPORT_SYMBOL_GPL(spi_res_add);
  */
 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
 {
-	struct spi_res *res;
-
-	while (!list_empty(&message->resources)) {
-		res = list_last_entry(&message->resources,
-				      struct spi_res, entry);
+	struct spi_res *res, *tmp;
 
+	list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
 		if (res->release)
 			res->release(ctlr, message, res->data);