net: lantiq: Fix use correct return type for ndo_start_xmit()

The method ndo_start_xmit() returns a value of type netdev_tx_t. Fix
the ndo function to use the correct type.
Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/lantiq_xrx200.c

@@ -276,7 +276,8 @@ static int xrx200_tx_housekeeping(struct napi_struct *napi, int budget)
 	return pkts;
 }
 
-static int xrx200_start_xmit(struct sk_buff *skb, struct net_device *net_dev)
+static netdev_tx_t xrx200_start_xmit(struct sk_buff *skb,
+				     struct net_device *net_dev)
 {
 	struct xrx200_priv *priv = netdev_priv(net_dev);
 	struct xrx200_chan *ch = &priv->chan_tx;