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

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/drivers/spi/spi-octeon.c b/drivers/spi/spi-octeon.c
index 67249a4..862ef30 100644
--- a/drivers/spi/spi-octeon.c
+++ b/drivers/spi/spi-octeon.c
@@ -179,7 +179,8 @@
 	}
 
 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
-		bool last_xfer = &xfer->transfer_list == msg->transfers.prev;
+		bool last_xfer = list_is_last(&xfer->transfer_list,
+					      &msg->transfers);
 		int r = octeon_spi_do_transfer(p, msg, xfer, last_xfer);
 		if (r < 0) {
 			status = r;