net: Convert nfnl_queue_net_ops

These pernet_operations register and unregister net::nf::queue_handler
and /proc entry. The handler is accessed only under RCU, so this looks
safe to convert them.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netfilter/nfnetlink_queue.c

@@ -1528,6 +1528,7 @@ static struct pernet_operations nfnl_queue_net_ops = {
 	.exit_batch	= nfnl_queue_net_exit_batch,
 	.id		= &nfnl_queue_net_id,
 	.size		= sizeof(struct nfnl_queue_net),
+	.async		= true,
 };
 
 static int __init nfnetlink_queue_init(void)