ieee802154: 6lowpan: set IFLA_LINK

Otherwise NetworkManager (and iproute alike) is not able to identify the
parent IEEE 802.15.4 interface of a 6LoWPAN link.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Acked-by: Alexander Aring <aring@mojatatu.com>
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>

net/ieee802154/6lowpan/core.c

@@ -90,12 +90,18 @@ static int lowpan_neigh_construct(struct net_device *dev, struct neighbour *n)
 	return 0;
 }
 
+static int lowpan_get_iflink(const struct net_device *dev)
+{
+	return lowpan_802154_dev(dev)->wdev->ifindex;
+}
+
 static const struct net_device_ops lowpan_netdev_ops = {
 	.ndo_init		= lowpan_dev_init,
 	.ndo_start_xmit		= lowpan_xmit,
 	.ndo_open		= lowpan_open,
 	.ndo_stop		= lowpan_stop,
 	.ndo_neigh_construct    = lowpan_neigh_construct,
+	.ndo_get_iflink         = lowpan_get_iflink,
 };
 
 static void lowpan_setup(struct net_device *ldev)