net: Convert tipc_net_ops

TIPC looks concentrated in itself, and other pernet_operations
seem not touching its entities.

tipc_net_ops look pernet-divided, and they should be safe to
be executed in parallel for several net the same time.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/core.c

@@ -105,6 +105,7 @@ static struct pernet_operations tipc_net_ops = {
 	.exit = tipc_exit_net,
 	.id   = &tipc_net_id,
 	.size = sizeof(struct tipc_net),
+	.async = true,
 };
 
 static int __init tipc_init(void)