net: Convert bond_net_ops

These pernet_operations populate/depopulate /proc and /sys
entries. Exit method unregisters all net bond devices, and
it seems another pernet_operations are not interested in
foreign net bond list. So, it's possible to mark them async.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -4791,6 +4791,7 @@ static struct pernet_operations bond_net_ops = {
 	.exit = bond_net_exit,
 	.id   = &bond_net_id,
 	.size = sizeof(struct bond_net),
+	.async = true,
 };
 
 static int __init bonding_init(void)