net: ll_temac: Fix DMA map size bug

DMA allocates skb->len instead of headlen
which is used for DMA.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/xilinx/ll_temac_main.c

@@ -707,8 +707,8 @@ static int temac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 
 	cur_p->app0 |= STS_CTRL_APP0_SOP;
 	cur_p->len = skb_headlen(skb);
-	cur_p->phys = dma_map_single(ndev->dev.parent, skb->data, skb->len,
-				     DMA_TO_DEVICE);
+	cur_p->phys = dma_map_single(ndev->dev.parent, skb->data,
+				     skb_headlen(skb), DMA_TO_DEVICE);
 	cur_p->app4 = (unsigned long)skb;
 
 	for (ii = 0; ii < num_frag; ii++) {