[NETFILTER]: ipt_TTL: fix checksum update bug

Fix regression introduced by the incremental checksum patches.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/netfilter/ipt_TTL.c

@@ -54,8 +54,8 @@ ipt_ttl_target(struct sk_buff **pskb,
 	}
 
 	if (new_ttl != iph->ttl) {
-		iph->check = nf_csum_update((iph->ttl << 8) ^ 0xFFFF,
-					    new_ttl << 8,
+		iph->check = nf_csum_update(ntohs((iph->ttl << 8)) ^ 0xFFFF,
+					    ntohs(new_ttl << 8),
 					    iph->check);
 		iph->ttl = new_ttl;
 	}