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/sfc/tx.c b/drivers/net/sfc/tx.c
index 14a1478..489c4de 100644
--- a/drivers/net/sfc/tx.c
+++ b/drivers/net/sfc/tx.c
@@ -138,8 +138,8 @@
  * Returns NETDEV_TX_OK or NETDEV_TX_BUSY
  * You must hold netif_tx_lock() to call this function.
  */
-static int efx_enqueue_skb(struct efx_tx_queue *tx_queue,
-			   struct sk_buff *skb)
+static netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue,
+					 struct sk_buff *skb)
 {
 	struct efx_nic *efx = tx_queue->efx;
 	struct pci_dev *pci_dev = efx->pci_dev;
@@ -152,7 +152,7 @@
 	unsigned int dma_len;
 	bool unmap_single;
 	int q_space, i = 0;
-	int rc = NETDEV_TX_OK;
+	netdev_tx_t rc = NETDEV_TX_OK;
 
 	EFX_BUG_ON_PARANOID(tx_queue->write_count != tx_queue->insert_count);
 
@@ -353,14 +353,11 @@
  *
  * Context: netif_tx_lock held
  */
-inline int efx_xmit(struct efx_nic *efx,
-		    struct efx_tx_queue *tx_queue, struct sk_buff *skb)
+inline netdev_tx_t efx_xmit(struct efx_nic *efx,
+			   struct efx_tx_queue *tx_queue, struct sk_buff *skb)
 {
-	int rc;
-
 	/* Map fragments for DMA and add to TX queue */
-	rc = efx_enqueue_skb(tx_queue, skb);
-	return rc;
+	return efx_enqueue_skb(tx_queue, skb);
 }
 
 /* Initiate a packet transmission.  We use one channel per CPU
@@ -372,7 +369,8 @@
  * Note that returning anything other than NETDEV_TX_OK will cause the
  * OS to free the skb.
  */
-int efx_hard_start_xmit(struct sk_buff *skb, struct net_device *net_dev)
+netdev_tx_t efx_hard_start_xmit(struct sk_buff *skb,
+				      struct net_device *net_dev)
 {
 	struct efx_nic *efx = netdev_priv(net_dev);
 	struct efx_tx_queue *tx_queue;