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/ipv4/ipip.c b/net/ipv4/ipip.c
index bfbcc85..5c81f6e 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -272,6 +272,7 @@
 	.ndo_do_ioctl	= ipip_tunnel_ioctl,
 	.ndo_change_mtu = ip_tunnel_change_mtu,
 	.ndo_get_stats64 = ip_tunnel_get_stats64,
+	.ndo_get_iflink = ip_tunnel_get_iflink,
 };
 
 #define IPIP_FEATURES (NETIF_F_SG |		\
@@ -286,7 +287,6 @@
 
 	dev->type		= ARPHRD_TUNNEL;
 	dev->flags		= IFF_NOARP;
-	dev->iflink		= 0;
 	dev->addr_len		= 4;
 	dev->features		|= NETIF_F_LLTX;
 	netif_keep_dst(dev);