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>
diff --git a/include/net/gen_stats.h b/include/net/gen_stats.h
index dcf5bfa..d136b52 100644
--- a/include/net/gen_stats.h
+++ b/include/net/gen_stats.h
@@ -45,6 +45,6 @@
 extern int gen_replace_estimator(struct gnet_stats_basic *bstats,
 				 struct gnet_stats_rate_est *rate_est,
 				 spinlock_t *stats_lock, struct nlattr *opt);
-extern int gen_estimator_active(const struct gnet_stats_rate_est *rate_est);
-
+extern bool gen_estimator_active(const struct gnet_stats_basic *bstats,
+				 const struct gnet_stats_rate_est *rate_est);
 #endif