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/jme.c b/drivers/net/jme.c
index e7068c7..1d2a325 100644
--- a/drivers/net/jme.c
+++ b/drivers/net/jme.c
@@ -1931,7 +1931,7 @@
  * This function is already protected by netif_tx_lock()
  */
 
-static int
+static netdev_tx_t
 jme_start_xmit(struct sk_buff *skb, struct net_device *netdev)
 {
 	struct jme_adapter *jme = netdev_priv(netdev);