ibmveth: Fix DMA unmap error

Commit 6e8ab30e (ibmveth: Add scatter-gather support) introduced a
DMA mapping API inconsistency resulting in dma_unmap_page getting
called on memory mapped via dma_map_single. This was seen when
CONFIG_DMA_API_DEBUG was enabled. Fix up this API usage inconsistency.
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Acked-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org> # v2.6.37+
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ibmveth.c

@@ -1026,7 +1026,12 @@ static netdev_tx_t ibmveth_start_xmit(struct sk_buff *skb,
 		netdev->stats.tx_bytes += skb->len;
 	}
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags + 1; i++)
+	dma_unmap_single(&adapter->vdev->dev,
+			 descs[0].fields.address,
+			 descs[0].fields.flags_len & IBMVETH_BUF_LEN_MASK,
+			 DMA_TO_DEVICE);
+
+	for (i = 1; i < skb_shinfo(skb)->nr_frags + 1; i++)
 		dma_unmap_page(&adapter->vdev->dev, descs[i].fields.address,
 			       descs[i].fields.flags_len & IBMVETH_BUF_LEN_MASK,
 			       DMA_TO_DEVICE);