stmmac: fix race in transmit time stamping.

Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/stmmac/stmmac_main.c

@@ -1079,10 +1079,10 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	dev->stats.tx_bytes += skb->len;
 
-	priv->hw->dma->enable_dma_transmission(priv->ioaddr);
-
 	skb_tx_timestamp(skb);
 
+	priv->hw->dma->enable_dma_transmission(priv->ioaddr);
+
 	return NETDEV_TX_OK;
 }