dm cache: remove needless request_queue NULL pointer checks

Since commit ff9ea323816d ("block, bdi: an active gendisk always has a
request_queue associated with it") the request_queue pointer returned
from bdev_get_queue() shall never be NULL.

Signed-off-by: Xu Wang <[e-mail]>
Signed-off-by: Mike Snitzer <[e-mail]>

drivers/md/dm-cache-target.c

···
 {
 	struct request_queue *q = bdev_get_queue(origin_bdev);
 
-	return q && blk_queue_discard(q);
+	return blk_queue_discard(q);
 }
 
 /*