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>

drivers/net/wan/hd64570.c

@@ -658,7 +658,6 @@ static netdev_tx_t sca_xmit(struct sk_buff *skb, struct net_device *dev)
 #endif
 	writew(len, &desc->len);
 	writeb(ST_TX_EOM, &desc->stat);
-	dev->trans_start = jiffies;
 
 	port->txin = next_desc(port, port->txin, 1);
 	sca_outw(desc_offset(port, port->txin, 1),