ip6tnl: allow to use rtnl ops on fb tunnel

rtnl ops where introduced by c075b130 ("ip6tnl: advertise tunnel param via
rtnl"), but I forget to assign rtnl ops to fb tunnels.

Now that it is done, we must remove the explicit call to
unregister_netdevice_queue(), because  the fallback tunnel is added to the queue
in ip6_tnl_destroy_tunnels() when checking rtnl_link_ops of all netdevices (this
is valid since commit 0bd87628 ("ip6tnl: add x-netns support")).
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/ip6_tunnel.c

@@ -1731,8 +1731,6 @@ static void __net_exit ip6_tnl_destroy_tunnels(struct ip6_tnl_net *ip6n)
 		}
 	}
 
-	t = rtnl_dereference(ip6n->tnls_wc[0]);
-	unregister_netdevice_queue(t->dev, &list);
 	unregister_netdevice_many(&list);
 }
 
@@ -1752,6 +1750,7 @@ static int __net_init ip6_tnl_init_net(struct net *net)
 	if (!ip6n->fb_tnl_dev)
 		goto err_alloc_dev;
 	dev_net_set(ip6n->fb_tnl_dev, net);
+	ip6n->fb_tnl_dev->rtnl_link_ops = &ip6_link_ops;
 	/* FB netdevice is special: we have one, and only one per netns.
 	 * Allowing to move it to another netns is clearly unsafe.
 	 */