mv643xx_eth: enable transmit time stamping.

This patch enables software (and phy device) transmit time stamping.
Compile tested only.
Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/mv643xx_eth.c

@@ -840,6 +840,8 @@ static int txq_submit_skb(struct tx_queue *txq, struct sk_buff *skb)
 
 	__skb_queue_tail(&txq->tx_skb, skb);
 
+	skb_tx_timestamp(skb);
+
 	/* ensure all other descriptors are written before first cmd_sts */
 	wmb();
 	desc->cmd_sts = cmd_sts;