[SK_BUFF]: Convert skb->end to sk_buff_data_t

Now to convert the last one, skb->data, that will allow many simplifications
and removal of some of the offset helpers.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/macb.c

@@ -576,7 +576,7 @@ static int macb_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	dev_dbg(&bp->pdev->dev,
 		"start_xmit: len %u head %p data %p tail %p end %p\n",
 		skb->len, skb->head, skb->data,
-		skb_tail_pointer(skb), skb->end);
+		skb_tail_pointer(skb), skb_end_pointer(skb));
 	dev_dbg(&bp->pdev->dev,
 		"data:");
 	for (i = 0; i < 16; i++)