netfilter: nf_conntrack: add nf_ct_kill()

Encapsulate the common

	if (del_timer(&ct->timeout))
		ct->timeout.function((unsigned long)ct)

sequence in a new function.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index 2dbd6c0..fc19ab2 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h
@@ -223,6 +223,8 @@
 	__nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, 0);
 }
 
+extern void nf_ct_kill(struct nf_conn *ct);
+
 /* These are for NAT.  Icky. */
 /* Update TCP window tracking data when NAT mangles the packet */
 extern void nf_conntrack_tcp_update(const struct sk_buff *skb,