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/3c505.c b/drivers/net/3c505.c
index 8d584f5..88d766e 100644
--- a/drivers/net/3c505.c
+++ b/drivers/net/3c505.c
@@ -1055,7 +1055,7 @@
 		   (stat & ACRF) ? "interrupt" : "command");
 	if (elp_debug >= 1)
 		pr_debug("%s: status %#02x\n", dev->name, stat);
-	dev->trans_start = jiffies;
+	dev->trans_start = jiffies; /* prevent tx timeout */
 	dev->stats.tx_dropped++;
 	netif_wake_queue(dev);
 }
@@ -1093,11 +1093,6 @@
 	if (elp_debug >= 3)
 		pr_debug("%s: packet of length %d sent\n", dev->name, (int) skb->len);
 
-	/*
-	 * start the transmit timeout
-	 */
-	dev->trans_start = jiffies;
-
 	prime_rx(dev);
 	spin_unlock_irqrestore(&adapter->lock, flags);
 	netif_start_queue(dev);