bpf: use skb_at_tc_ingress helper in tcf_bpf

We have a small skb_at_tc_ingress() helper for testing for ingress, so
make use of it. cls_bpf already uses it and so should act_bpf.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/act_bpf.c

@@ -39,10 +39,10 @@ static struct tc_action_ops act_bpf_ops;
 static int tcf_bpf(struct sk_buff *skb, const struct tc_action *act,
 		   struct tcf_result *res)
 {
+	bool at_ingress = skb_at_tc_ingress(skb);
 	struct tcf_bpf *prog = to_bpf(act);
 	struct bpf_prog *filter;
 	int action, filter_res;
-	bool at_ingress = G_TC_AT(skb->tc_verd) & AT_INGRESS;
 
 	tcf_lastuse_update(&prog->tcf_tm);
 	bstats_cpu_update(this_cpu_ptr(prog->common.cpu_bstats), skb);