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/atp.c b/drivers/net/atp.c
index 2bd1a5c..75ff0c5 100644
--- a/drivers/net/atp.c
+++ b/drivers/net/atp.c
@@ -547,7 +547,7 @@
 	dev->stats.tx_errors++;
 	/* Try to restart the adapter. */
 	hardware_init(dev);
-	dev->trans_start = jiffies;
+	dev->trans_start = jiffies; /* prevent tx timeout */
 	netif_wake_queue(dev);
 	dev->stats.tx_errors++;
 }
@@ -586,7 +586,6 @@
 	write_reg(ioaddr, IMR, ISR_RxOK | ISR_TxErr | ISR_TxOK);
 	write_reg_high(ioaddr, IMR, ISRh_RxErr);
 
-	dev->trans_start = jiffies;
 	dev_kfree_skb (skb);
 	return NETDEV_TX_OK;
 }