net: dont update dev->trans_start in 10GB drivers

Followup of commits 9d21493b4b
and 08baf56108
(net: tx scalability works : trans_start)
(net: txq_trans_update() helper)

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

Exceptions are NETIF_F_LLTX drivers (vxge & tehuti)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ixgb/ixgb_main.c

@@ -1488,7 +1488,6 @@ ixgb_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
 
 	if (count) {
 		ixgb_tx_queue(adapter, count, vlan_id, tx_flags);
-		netdev->trans_start = jiffies;
 		/* Make sure there is space in the ring for the next send. */
 		ixgb_maybe_stop_tx(netdev, &adapter->tx_ring, DESC_NEEDED);