[NET]: Annotate __skb_checksum_complete() and friends.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netfilter_ipv6.h b/include/linux/netfilter_ipv6.h
index d97e268..ab81a6d 100644
--- a/include/linux/netfilter_ipv6.h
+++ b/include/linux/netfilter_ipv6.h
@@ -74,7 +74,7 @@
 
 #ifdef CONFIG_NETFILTER
 extern int ip6_route_me_harder(struct sk_buff *skb);
-extern unsigned int nf_ip6_checksum(struct sk_buff *skb, unsigned int hook,
+extern __sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook,
 				    unsigned int dataoff, u_int8_t protocol);
 
 extern int ipv6_netfilter_init(void);