pkt_sched: Kill set but unused variable 'protocol' in tc_classify()

I checked the history and this has been like this since the
beginning of time.

Signed-off-by: David S. Miller <[e-mail]>

net/sched/sch_api.c

···
 {
 	int err = 0;
 #ifdef CONFIG_NET_CLS_ACT
-	__be16 protocol;
 	struct tcf_proto *otp = tp;
 reclassify:
-	protocol = skb->protocol;
 #endif
 
 	err = tc_classify_compat(skb, tp, res);