ipip,gre,vti,sit: implement ndo_get_iflink

Don't use dev->iflink anymore.

CC: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index e6b9f51..6cf2026 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1076,7 +1076,6 @@
 		if (dev->mtu < IPV6_MIN_MTU)
 			dev->mtu = IPV6_MIN_MTU;
 	}
-	dev->iflink = tunnel->parms.link;
 }
 
 static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p)
@@ -1336,6 +1335,7 @@
 	.ndo_do_ioctl	= ipip6_tunnel_ioctl,
 	.ndo_change_mtu	= ipip6_tunnel_change_mtu,
 	.ndo_get_stats64 = ip_tunnel_get_stats64,
+	.ndo_get_iflink = ip_tunnel_get_iflink,
 };
 
 static void ipip6_dev_free(struct net_device *dev)
@@ -1366,7 +1366,6 @@
 	dev->mtu		= ETH_DATA_LEN - t_hlen;
 	dev->flags		= IFF_NOARP;
 	netif_keep_dst(dev);
-	dev->iflink		= 0;
 	dev->addr_len		= 4;
 	dev->features		|= NETIF_F_LLTX;
 	dev->features		|= SIT_FEATURES;