block: fix resource leak in blk_register_queue() error path

When registering a queue fails after blk_mq_sysfs_register() is
successful but the function later encounters an error, we need
to clean up the blk_mq_sysfs resources.

Add the missing blk_mq_sysfs_unregister() call in the error path
to properly clean up these resources and prevent a memory leak.

Fixes: 320ae51 ("blk-mq: new multi-queue block IO queueing mechanism")
Signed-off-by: Zheng Qixing <zhengqixing@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20250412092554.475218-1-zhengqixing@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-sysfs.c

@@ -909,6 +909,8 @@ int blk_register_queue(struct gendisk *disk)
 out_debugfs_remove:
 	blk_debugfs_remove(disk);
 	mutex_unlock(&q->sysfs_lock);
+	if (queue_is_mq(q))
+		blk_mq_sysfs_unregister(disk);
 out_put_queue_kobj:
 	kobject_put(&disk->queue_kobj);
 	return ret;