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

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

Followup of commits 3bc17055cb657ee585c284f65586ba17e14954a7
and 7cc9bdd11e537c8b48a4cc7a41c419879c594521
(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>