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/ibmveth.c b/drivers/net/ibmveth.c
index 0d2c3ac..092fb9d 100644
--- a/drivers/net/ibmveth.c
+++ b/drivers/net/ibmveth.c
@@ -957,7 +957,7 @@
 	} else {
 		tx_packets++;
 		tx_bytes += skb->len;
-		netdev->trans_start = jiffies;
+		netdev->trans_start = jiffies; /* NETIF_F_LLTX driver :( */
 	}
 
 	if (!used_bounce)