Revert "net: sched: act: add extack for lookup callback"

This reverts commit 331a9295de23 ("net: sched: act: add extack for lookup callback").

This extack is never used after 6 months... In fact, it can be just
set in the caller, right after ->lookup().

Cc: Alexander Aring <aring@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/act_api.h b/include/net/act_api.h
index 9703034..c6f195b 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -85,8 +85,7 @@ struct tc_action_ops {
 		       struct tcf_result *); /* called under RCU BH lock*/
 	int     (*dump)(struct sk_buff *, struct tc_action *, int, int);
 	void	(*cleanup)(struct tc_action *);
-	int     (*lookup)(struct net *net, struct tc_action **a, u32 index,
-			  struct netlink_ext_ack *extack);
+	int     (*lookup)(struct net *net, struct tc_action **a, u32 index);
 	int     (*init)(struct net *net, struct nlattr *nla,
 			struct nlattr *est, struct tc_action **act, int ovr,
 			int bind, bool rtnl_held,