[NET]: Annotate callers of csum_fold() in net/*

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 523141e..edd3246 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -88,7 +88,7 @@
 	psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 
 	if (skb->ip_summed == CHECKSUM_COMPLETE &&
-	    !(u16)csum_fold(csum_add(psum, skb->csum)))
+	    !csum_fold(csum_add(psum, skb->csum)))
 		return 0;
 
 	skb->csum = psum;