net: caif: 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: NYunjian Wang <wangyunjian@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/caif/chnl_net.c

@@ -211,7 +211,8 @@ static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
 	}
 }
 
-static int chnl_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t chnl_net_start_xmit(struct sk_buff *skb,
+				       struct net_device *dev)
 {
 	struct chnl_net *priv;
 	struct cfpkt *pkt = NULL;