caif: fix cfv_netdev_tx()'s return type

The method ndo_start_xmit() is defined as returning an 'netdev_tx_t',
which is a typedef for an enum type, but the implementation in this
driver returns an 'int'.

Fix this by returning 'netdev_tx_t' in this driver too.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/caif/caif_virtio.c

@@ -519,7 +519,7 @@ static struct buf_info *cfv_alloc_and_copy_to_shm(struct cfv_info *cfv,
 }
 
 /* Put the CAIF packet on the virtio ring and kick the receiver */
-static int cfv_netdev_tx(struct sk_buff *skb, struct net_device *netdev)
+static netdev_tx_t cfv_netdev_tx(struct sk_buff *skb, struct net_device *netdev)
 {
 	struct cfv_info *cfv = netdev_priv(netdev);
 	struct buf_info *buf_info;