nbd: Fix incorrect error handle when first_minor is illegal in nbd_de…

…v_add

If first_minor is illegal will goto out_free_idr label, this will miss
cleanup disk.

Fixes: b1a8116 ("block: nbd: add sanity check for first_minor")
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20211102015237.2309763-4-yebin10@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/nbd.c

@@ -1814,7 +1814,7 @@ static struct nbd_device *nbd_dev_add(int index, unsigned int refs)
 	disk->first_minor = index << part_shift;
 	if (disk->first_minor < index || disk->first_minor > MINORMASK) {
 		err = -EINVAL;
-		goto out_free_idr;
+		goto out_err_disk;
 	}
 
 	disk->minors = 1 << part_shift;