thermal: core: add a comment describing the power actor section

Simply marking the power actor section and adding a
comment describing it.

Cc: Zhang Rui <rui.zhang@intel.com>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NEduardo Valentin <edubezval@gmail.com>
Signed-off-by: NZhang Rui <rui.zhang@intel.com>

drivers/thermal/thermal_core.c

@@ -461,6 +461,13 @@ static void thermal_zone_device_check(struct work_struct *work)
 	thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
 }
 
+/*
+ * Power actor section: interface to power actors to estimate power
+ *
+ * Set of functions used to interact to cooling devices that know
+ * how to estimate their devices power consumption.
+ */
+
 /**
  * power_actor_get_max_power() - get the maximum power that a cdev can consume
  * @cdev:	pointer to &thermal_cooling_device