can: sun4i: fix sun4ican_start_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 <luc.vanoostenryck@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/sun4i_can.c

@@ -409,7 +409,7 @@ static int sun4ican_set_mode(struct net_device *dev, enum can_mode mode)
  * xx xx xx xx         ff         ll 00 11 22 33 44 55 66 77
  * [ can_id ] [flags] [len] [can data (up to 8 bytes]
  */
-static int sun4ican_start_xmit(struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t sun4ican_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct sun4ican_priv *priv = netdev_priv(dev);
 	struct can_frame *cf = (struct can_frame *)skb->data;