caif: fix caif_xmit()'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 <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/caif/caif_serial.c

···
 	return tty_wr;
 }
 
-static int caif_xmit(struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t caif_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct ser_device *ser;