netfilter: use_nf_conn_expires helper in more places

... so we don't need to touch all of these places when we get rid of the
timer in nf_conn.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 050bb34..68800c1 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -149,10 +149,7 @@
 
 static int ctnetlink_dump_timeout(struct sk_buff *skb, const struct nf_conn *ct)
 {
-	long timeout = ((long)ct->timeout.expires - (long)jiffies) / HZ;
-
-	if (timeout < 0)
-		timeout = 0;
+	long timeout = nf_ct_expires(ct) / HZ;
 
 	if (nla_put_be32(skb, CTA_TIMEOUT, htonl(timeout)))
 		goto nla_put_failure;