net: Convert fib6_rules_net_ops

These pernet_operations register and unregister
net::ipv6.fib6_rules_ops, which are used for
routing. It looks like there are no pernet_operations,
which send ipv6 packages to another net, so we
are able to mark them as async.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/fib6_rules.c

@@ -368,6 +368,7 @@ static void __net_exit fib6_rules_net_exit(struct net *net)
 static struct pernet_operations fib6_rules_net_ops = {
 	.init = fib6_rules_net_init,
 	.exit = fib6_rules_net_exit,
+	.async = true,
 };
 
 int __init fib6_rules_init(void)