sch_choke: Remove classid from choke_skb_cb.

Suggested by Cong Wang.
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/sch_choke.c

@@ -131,7 +131,6 @@ static void choke_drop_by_idx(struct Qdisc *sch, unsigned int idx,
 }
 
 struct choke_skb_cb {
-	u16			classid;
 	u8			keys_valid;
 	struct			flow_keys_digest keys;
 };