netdev: convert pseudo drivers to netdev_tx_t

These are all drivers that don't touch real hardware.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 99eed9f..f893cd4 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -184,7 +184,8 @@
 	return NULL;
 }
 
-static int macvlan_start_xmit(struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t macvlan_start_xmit(struct sk_buff *skb,
+				      struct net_device *dev)
 {
 	const struct macvlan_dev *vlan = netdev_priv(dev);
 	unsigned int len = skb->len;