thermal: gov_fair_share: Rearrange get_trip_level()

Make get_trip_level() use for_each_trip() to iterate over trip points
and make it call thermal_zone_trip_id() to obtain the integer ID of a
given trip point so as to avoid relying on the knowledge of struct
thermal_zone_device internals.

The general functionality is not expected to be changed.

This change causes the governor to use trip pointers instead of trip
indices everywhere except for the fair_share_throttle() second argument
that will be modified subsequently along with the definition of the
governor .throttle() callback.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>

Author: rafaeljw

drivers/thermal/gov_fair_share.c

@@ -15,29 +15,27 @@
 
 #include "thermal_core.h"
 
-/**
- * get_trip_level: - obtains the current trip level for a zone
- * @tz:		thermal zone device
- */
 static int get_trip_level(struct thermal_zone_device *tz)
 {
-	struct thermal_trip trip;
-	int count;
+	const struct thermal_trip *trip, *level_trip = NULL;
+	int trip_level;
 
-	for (count = 0; count < tz->num_trips; count++) {
-		__thermal_zone_get_trip(tz, count, &trip);
-		if (tz->temperature < trip.temperature)
+	for_each_trip(tz, trip) {
+		if (trip->temperature >= tz->temperature)
 			break;
+
+		level_trip = trip;
 	}
 
-	/*
-	 * count > 0 only if temperature is greater than first trip
-	 * point, in which case, trip_point = count - 1
-	 */
-	if (count > 0)
-		trace_thermal_zone_trip(tz, count - 1, trip.type);
+	/*  Bail out if the temperature is not greater than any trips. */
+	if (!level_trip)
+		return 0;
+
+	trip_level = thermal_zone_trip_id(tz, level_trip);
+
+	trace_thermal_zone_trip(tz, trip_level, level_trip->type);
 
-	return count;
+	return trip_level;
 }
 
 static long get_target_state(struct thermal_zone_device *tz,