[NETFILTER]: Convert old checksum helper names

Kill the defines again, convert to the new checksum helper names and
remove the dependency of NET_ACT_NAT on NETFILTER.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/netfilter/nf_nat_core.c b/net/ipv4/netfilter/nf_nat_core.c
index d237511..746c2ef 100644
--- a/net/ipv4/netfilter/nf_nat_core.c
+++ b/net/ipv4/netfilter/nf_nat_core.c
@@ -372,10 +372,10 @@
 	iph = (void *)skb->data + iphdroff;
 
 	if (maniptype == IP_NAT_MANIP_SRC) {
-		nf_csum_replace4(&iph->check, iph->saddr, target->src.u3.ip);
+		csum_replace4(&iph->check, iph->saddr, target->src.u3.ip);
 		iph->saddr = target->src.u3.ip;
 	} else {
-		nf_csum_replace4(&iph->check, iph->daddr, target->dst.u3.ip);
+		csum_replace4(&iph->check, iph->daddr, target->dst.u3.ip);
 		iph->daddr = target->dst.u3.ip;
 	}
 	return 1;