congestion_wait(): don't use WRITE

commit 8aa7e847 (Fix congestion_wait() sync/async vs read/write
confusion) replace WRITE with BLK_RW_ASYNC.  Unfortunately, concurrent mm
development made the unchanged place accidentally.

This patch fixes it too.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmscan.c

@@ -1088,7 +1088,7 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
 	int lumpy_reclaim = 0;
 
 	while (unlikely(too_many_isolated(zone, file, sc))) {
-		congestion_wait(WRITE, HZ/10);
+		congestion_wait(BLK_RW_ASYNC, HZ/10);
 
 		/* We are about to die and free our memory. Return now. */
 		if (fatal_signal_pending(current))