net: Convert netlink_tap_net_ops

These pernet_operations init just allocated net memory,
and they obviously can be executed in parallel in any
others.

v3: New
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Andrei Vagin <avagin@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netlink/af_netlink.c

@@ -253,6 +253,7 @@ static struct pernet_operations netlink_tap_net_ops = {
 	.exit = netlink_tap_exit_net,
 	.id   = &netlink_tap_net_id,
 	.size = sizeof(struct netlink_tap_net),
+	.async = true,
 };
 
 static bool netlink_filter_tap(const struct sk_buff *skb)