spi: tegra114: Use list_is_last() instead of open-coded

For better readability, and then we can remove the comment for last transfer.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/spi/spi-tegra114.c

@@ -853,8 +853,8 @@ static int tegra_spi_transfer_one_message(struct spi_master *master,
 					SPI_COMMAND1);
 			tegra_spi_transfer_delay(xfer->delay_usecs);
 			goto exit;
-		} else if (msg->transfers.prev == &xfer->transfer_list) {
-			/* This is the last transfer in message */
+		} else if (list_is_last(&xfer->transfer_list,
+					&msg->transfers)) {
 			if (xfer->cs_change)
 				tspi->cs_control = spi;
 			else {