block: fix blk_rq_map_kern bio direction flag

This bug was introduced in 7b6d91daee5cac6402186ff224c3af39d79f4a0e
"block: unify flags for struct bio and struct request"

Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

block/blk-map.c

diff --git a/block/blk-map.c b/block/blk-map.c
index c65d759..ade0a08 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -307,7 +307,7 @@
 		return PTR_ERR(bio);
 
 	if (rq_data_dir(rq) == WRITE)
-		bio->bi_rw |= (1 << REQ_WRITE);
+		bio->bi_rw |= REQ_WRITE;
 
 	if (do_copy)
 		rq->cmd_flags |= REQ_COPY_USER;