net: sched: constify tcf_proto and tc_action

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 2f64262..f2fb67e 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -365,10 +365,10 @@
 }
 #endif
 
-int tcf_action_exec(struct sk_buff *skb, struct tc_action *act,
+int tcf_action_exec(struct sk_buff *skb, const struct tc_action *act,
 		    struct tcf_result *res)
 {
-	struct tc_action *a;
+	const struct tc_action *a;
 	int ret = -1;
 
 	if (skb->tc_verd & TC_NCLS) {