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/qlge/qlge_main.c b/drivers/net/qlge/qlge_main.c
index 8dd266b..2205292 100644
--- a/drivers/net/qlge/qlge_main.c
+++ b/drivers/net/qlge/qlge_main.c
@@ -2103,7 +2103,7 @@
 				    iph->daddr, len, iph->protocol, 0);
 }
 
-static int qlge_send(struct sk_buff *skb, struct net_device *ndev)
+static netdev_tx_t qlge_send(struct sk_buff *skb, struct net_device *ndev)
 {
 	struct tx_ring_desc *tx_ring_desc;
 	struct ob_mac_iocb_req *mac_iocb_ptr;