[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/include/linux/skbuff.h b/include/linux/skbuff.h
index fcab543..14ec16d 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -274,7 +274,10 @@
 	unsigned int		len,
 				data_len,
 				mac_len;
-	__wsum			csum;
+	union {
+		__wsum		csum;
+		__u32		csum_offset;
+	};
 	__u32			priority;
 	__u8			local_df:1,
 				cloned:1,