mmc: mmc-test: use swap() in mmc_test_nonblock_transfer()

Use kernel.h macro definition.
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/card/mmc_test.c

@@ -820,9 +820,7 @@ static int mmc_test_nonblock_transfer(struct mmc_test_card *test,
 				mmc_test_nonblock_reset(&mrq1, &cmd1,
 							&stop1, &data1);
 		}
-		done_areq = cur_areq;
-		cur_areq = other_areq;
-		other_areq = done_areq;
+		swap(cur_areq, other_areq);
 		dev_addr += blocks;
 	}