blk-mq: remove legacy check in queue blk_freeze_queue()

Reviewed-by: NHannes Reinecke <hare@suse.com>
Tested-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

block/blk-mq.c

@@ -177,8 +177,6 @@ void blk_freeze_queue(struct request_queue *q)
 	 * exported to drivers as the only user for unfreeze is blk_mq.
 	 */
 	blk_freeze_queue_start(q);
-	if (!q->mq_ops)
-		blk_drain_queue(q);
 	blk_mq_freeze_queue_wait(q);
 }