Thermal: Add get trend, get instance API's to thermal_sys

This patch adds the following API's to thermal_sys.c, that
can be used by other Thermal drivers.
 * get_tz_trend: obtain the trend of the given thermal zone
 * get_thermal_instance: obtain the instance corresponding
   to the given tz, cdev and the trip point.

Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index 8611e3e..32af124 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -185,6 +185,10 @@
 		const struct thermal_cooling_device_ops *);
 void thermal_cooling_device_unregister(struct thermal_cooling_device *);
 
+int get_tz_trend(struct thermal_zone_device *, int);
+struct thermal_instance *get_thermal_instance(struct thermal_zone_device *,
+		struct thermal_cooling_device *, int);
+
 #ifdef CONFIG_NET
 extern int thermal_generate_netlink_event(u32 orig, enum events event);
 #else