block: don't autoload drivers on blk-cgroup configuration

Loading a driver just to configure blk-cgroup doesn't make sense, as that
assumes and already existing device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20250423053810.1683309-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Christoph Hellwig

block/blk-cgroup.c

@@ -797,7 +797,7 @@ int blkg_conf_open_bdev(struct blkg_conf_ctx *ctx)
 		return -EINVAL;
 	input = skip_spaces(input);
 
-	bdev = blkdev_get_no_open(MKDEV(major, minor), true);
+	bdev = blkdev_get_no_open(MKDEV(major, minor), false);
 	if (!bdev)
 		return -ENODEV;
 	if (bdev_is_partition(bdev)) {