[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/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 0ca8dea..dadf802 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1544,7 +1544,7 @@
 	return sk;
 }
 
-static int tcp_v4_checksum_init(struct sk_buff *skb)
+static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
 {
 	if (skb->ip_summed == CHECKSUM_COMPLETE) {
 		if (!tcp_v4_check(skb->h.th, skb->len, skb->nh.iph->saddr,