pkt_sched: gen_estimator: Optimize gen_estimator_active()

Since all other gen_estimator functions use bstats and rate_est params
together, and searching for them is optimized now, let's use this also
in gen_estimator_active(). The return type of gen_estimator_active()
is changed to bool, and gen_find_node() parameters to const, btw.

In tcf_act_police_locate() a check for ACT_P_CREATED is added before
calling gen_estimator_active().

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/act_police.c

@@ -183,7 +183,9 @@ override:
 		if (R_tab == NULL)
 			goto failure;
 
-		if (!est && !gen_estimator_active(&police->tcf_rate_est)) {
+		if (!est && (ret == ACT_P_CREATED ||
+			     !gen_estimator_active(&police->tcf_bstats,
+						   &police->tcf_rate_est))) {
 			err = -EINVAL;
 			goto failure;
 		}