[NET]: Split skb->csum

... into anonymous union of __wsum and __u32 (csum and csum_offset resp.)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ixgb/ixgb_main.c b/drivers/net/ixgb/ixgb_main.c
index e09f575..7b12721 100644
--- a/drivers/net/ixgb/ixgb_main.c
+++ b/drivers/net/ixgb/ixgb_main.c
@@ -1249,7 +1249,7 @@
 	if(likely(skb->ip_summed == CHECKSUM_PARTIAL)) {
 		struct ixgb_buffer *buffer_info;
 		css = skb->h.raw - skb->data;
-		cso = (skb->h.raw + skb->csum) - skb->data;
+		cso = css + skb->csum_offset;
 
 		i = adapter->tx_ring.next_to_use;
 		context_desc = IXGB_CONTEXT_DESC(adapter->tx_ring, i);