net: Convert ip_tables_net_ops, udplite6_net_ops and xt_net_ops

ip_tables_net_ops and udplite6_net_ops create and destroy /proc entries.
xt_net_ops does nothing.

So, we are able to mark them async.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/netfilter/ip_tables.c

@@ -1911,6 +1911,7 @@ static void __net_exit ip_tables_net_exit(struct net *net)
 static struct pernet_operations ip_tables_net_ops = {
 	.init = ip_tables_net_init,
 	.exit = ip_tables_net_exit,
+	.async = true,
 };
 
 static int __init ip_tables_init(void)

net/ipv6/udplite.c

@@ -123,6 +123,7 @@ static void __net_exit udplite6_proc_exit_net(struct net *net)
 static struct pernet_operations udplite6_net_ops = {
 	.init = udplite6_proc_init_net,
 	.exit = udplite6_proc_exit_net,
+	.async = true,
 };
 
 int __init udplite6_proc_init(void)

net/netfilter/x_tables.c

@@ -1765,6 +1765,7 @@ static void __net_exit xt_net_exit(struct net *net)
 static struct pernet_operations xt_net_ops = {
 	.init = xt_net_init,
 	.exit = xt_net_exit,
+	.async = true,
 };
 
 static int __init xt_init(void)