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_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index 958a145..4e7becd 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -224,8 +224,7 @@
 	seq_printf(s, "%-8s %u %-8s %u %ld ",
 		   l3proto->name, nf_ct_l3num(ct),
 		   l4proto->name, nf_ct_protonum(ct),
-		   timer_pending(&ct->timeout)
-		   ? (long)(ct->timeout.expires - jiffies)/HZ : 0);
+		   nf_ct_expires(ct)  / HZ);
 
 	if (l4proto->print_conntrack)
 		l4proto->print_conntrack(s, ct);