can: flexcan: fix flexcan_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: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/flexcan.c

@@ -523,7 +523,7 @@ static int flexcan_get_berr_counter(const struct net_device *dev,
 	return err;
 }
 
-static int flexcan_start_xmit(struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t flexcan_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	const struct flexcan_priv *priv = netdev_priv(dev);
 	struct can_frame *cf = (struct can_frame *)skb->data;