nbd: allow genl access outside init_net

NBD doesn't have much to do with networking, allow users outside
init_net to access the family.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20230224021301.1630703-1-kuba@kernel.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/nbd.c

@@ -2325,6 +2325,7 @@ static struct genl_family nbd_genl_family __ro_after_init = {
 	.n_small_ops	= ARRAY_SIZE(nbd_connect_genl_ops),
 	.resv_start_op	= NBD_CMD_STATUS + 1,
 	.maxattr	= NBD_ATTR_MAX,
+	.netnsok	= 1,
 	.policy = nbd_attr_policy,
 	.mcgrps		= nbd_mcast_grps,
 	.n_mcgrps	= ARRAY_SIZE(nbd_mcast_grps),