net-sched: change tcf_destroy_chain() to clear start of filter list

Pass double tcf_proto pointers to tcf_destroy_chain() to make it
clear the start of the filter list for more consistency.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index ab502ec..a87fc03 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -178,7 +178,7 @@
 extern struct Qdisc *qdisc_create_dflt(struct net_device *dev,
 				       struct Qdisc_ops *ops, u32 parentid);
 extern void tcf_destroy(struct tcf_proto *tp);
-extern void tcf_destroy_chain(struct tcf_proto *fl);
+extern void tcf_destroy_chain(struct tcf_proto **fl);
 
 static inline int __qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch,
 				       struct sk_buff_head *list)