l2tp: define "l2tpeth" device type

Export type of l2tpeth interfaces to userspace
(/sys/class/net/<iface>/uevent).
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Acked-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/l2tp/l2tp_eth.c

@@ -130,8 +130,13 @@ static const struct net_device_ops l2tp_eth_netdev_ops = {
 	.ndo_set_mac_address	= eth_mac_addr,
 };
 
+static struct device_type l2tpeth_type = {
+	.name = "l2tpeth",
+};
+
 static void l2tp_eth_dev_setup(struct net_device *dev)
 {
+	SET_NETDEV_DEVTYPE(dev, &l2tpeth_type);
 	ether_setup(dev);
 	dev->priv_flags		&= ~IFF_TX_SKB_SHARING;
 	dev->features		|= NETIF_F_LLTX;