spi: Use list_last_entry at appropriate places

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c
index bf98d63..390da9b 100644
--- a/drivers/spi/spi-dw.c
+++ b/drivers/spi/spi-dw.c
@@ -276,8 +276,7 @@
 	queue_work(dws->workqueue, &dws->pump_messages);
 	spin_unlock_irqrestore(&dws->lock, flags);
 
-	last_transfer = list_entry(msg->transfers.prev,
-					struct spi_transfer,
+	last_transfer = list_last_entry(&msg->transfers, struct spi_transfer,
 					transfer_list);
 
 	if (!last_transfer->cs_change && dws->cs_control)