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/qla3xxx.c b/drivers/net/qla3xxx.c
index 3e4b67a..4c61051 100644
--- a/drivers/net/qla3xxx.c
+++ b/drivers/net/qla3xxx.c
@@ -2572,7 +2572,8 @@
  * The IOCB is always the top of the chain followed by one or more
  * OALs (when necessary).
  */
-static int ql3xxx_send(struct sk_buff *skb, struct net_device *ndev)
+static netdev_tx_t ql3xxx_send(struct sk_buff *skb,
+			       struct net_device *ndev)
 {
 	struct ql3_adapter *qdev = (struct ql3_adapter *)netdev_priv(ndev);
 	struct ql3xxx_port_registers __iomem *port_regs = qdev->mem_map_registers;