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>
diff --git a/drivers/net/skfp/skfddi.c b/drivers/net/skfp/skfddi.c
index 888a14a..38a508b 100644
--- a/drivers/net/skfp/skfddi.c
+++ b/drivers/net/skfp/skfddi.c
@@ -107,7 +107,8 @@
 static void skfp_ctl_set_multicast_list_wo_lock(struct net_device *dev);
 static int skfp_ctl_set_mac_address(struct net_device *dev, void *addr);
 static int skfp_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
-static int skfp_send_pkt(struct sk_buff *skb, struct net_device *dev);
+static netdev_tx_t skfp_send_pkt(struct sk_buff *skb,
+				       struct net_device *dev);
 static void send_queued_packets(struct s_smc *smc);
 static void CheckSourceAddress(unsigned char *frame, unsigned char *hw_addr);
 static void ResetAdapter(struct s_smc *smc);
@@ -1056,7 +1057,8 @@
  * Side Effects:
  *   None
  */
-static int skfp_send_pkt(struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t skfp_send_pkt(struct sk_buff *skb,
+				       struct net_device *dev)
 {
 	struct s_smc *smc = netdev_priv(dev);
 	skfddi_priv *bp = &smc->os;