netdev: convert bulk of drivers to netdev_tx_t

In a couple of cases collapse some extra code like:
   int retval = NETDEV_TX_OK;
   ...
   return retval;
into
   return NETDEV_TX_OK;

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/at1700.c

@@ -159,7 +159,8 @@ struct net_local {
 static int at1700_probe1(struct net_device *dev, int ioaddr);
 static int read_eeprom(long ioaddr, int location);
 static int net_open(struct net_device *dev);
-static int	net_send_packet(struct sk_buff *skb, struct net_device *dev);
+static netdev_tx_t net_send_packet(struct sk_buff *skb,
+				   struct net_device *dev);
 static irqreturn_t net_interrupt(int irq, void *dev_id);
 static void net_rx(struct net_device *dev);
 static int net_close(struct net_device *dev);
@@ -595,7 +596,8 @@ static void net_tx_timeout (struct net_device *dev)
 }
 
 
-static int net_send_packet (struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t net_send_packet (struct sk_buff *skb,
+				    struct net_device *dev)
 {
 	struct net_local *lp = netdev_priv(dev);
 	int ioaddr = dev->base_addr;