dm: remove unnecessary assignment statement in alloc_dev()

Fixes: 74fe6ba9 ("dm: convert to blk_alloc_disk/blk_cleanup_disk")
Signed-off-by: Genjian Zhang <zhanggenjian@kylinos.cn>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

drivers/md/dm.c

@@ -2065,7 +2065,6 @@ static struct mapped_device *alloc_dev(int minor)
 	md->disk->minors = 1;
 	md->disk->flags |= GENHD_FL_NO_PART;
 	md->disk->fops = &dm_blk_dops;
-	md->disk->queue = md->queue;
 	md->disk->private_data = md;
 	sprintf(md->disk->disk_name, "dm-%d", minor);