net: trans_start cleanups

Now that core network takes care of trans_start updates, dont do it
in drivers themselves, if possible. Drivers can avoid one cache miss
(on dev->trans_start) in their start_xmit() handler.

Exceptions are NETIF_F_LLTX drivers

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/starfire.c b/drivers/net/starfire.c
index 8a6d27c..e19b5a1 100644
--- a/drivers/net/starfire.c
+++ b/drivers/net/starfire.c
@@ -1173,7 +1173,7 @@
 
 	/* Trigger an immediate transmit demand. */
 
-	dev->trans_start = jiffies;
+	dev->trans_start = jiffies; /* prevent tx timeout */
 	np->stats.tx_errors++;
 	netif_wake_queue(dev);
 }
@@ -1312,8 +1312,6 @@
 	if ((np->cur_tx - np->dirty_tx) + 4 > TX_RING_SIZE)
 		netif_stop_queue(dev);
 
-	dev->trans_start = jiffies;
-
 	return NETDEV_TX_OK;
 }