net : enable tx time stamping in the vde driver.

This new version moves the skb_tx_timestamp in the main uml
driver. This should avoid the need to call this function in each
transport (vde, slirp, tuntap, ...). It also add support for ethtool
get_ts_info.
Signed-off-by: Paul Chavent <paul.chavent@onera.fr>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/drivers/net_kern.c

@@ -218,6 +218,7 @@ static int uml_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	spin_lock_irqsave(&lp->lock, flags);
 
 	len = (*lp->write)(lp->fd, skb, lp);
+	skb_tx_timestamp(skb);
 
 	if (len == skb->len) {
 		dev->stats.tx_packets++;
@@ -281,6 +282,7 @@ static void uml_net_get_drvinfo(struct net_device *dev,
 static const struct ethtool_ops uml_net_ethtool_ops = {
 	.get_drvinfo	= uml_net_get_drvinfo,
 	.get_link	= ethtool_op_get_link,
+	.get_ts_info	= ethtool_op_get_ts_info,
 };
 
 static void uml_net_user_timer_expire(unsigned long _conn)