rionet: 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/rionet.c

@@ -166,7 +166,8 @@ static int rionet_queue_tx_msg(struct sk_buff *skb, struct net_device *ndev,
 	return 0;
 }
 
-static int rionet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
+static netdev_tx_t rionet_start_xmit(struct sk_buff *skb,
+				     struct net_device *ndev)
 {
 	int i;
 	struct rionet_private *rnet = netdev_priv(ndev);