thermal: cpu_cooling: update kernel-doc comment for cpufreq_cooling_unregister

Update comments for this exported function.
Signed-off-by: NEduardo Valentin <eduardo.valentin@ti.com>
Acked-by: NAmit Daniel Kachhap <amit.daniel@samsung.com>
Signed-off-by: NZhang Rui <rui.zhang@intel.com>

drivers/thermal/cpu_cooling.c

@@ -485,6 +485,8 @@ EXPORT_SYMBOL_GPL(cpufreq_cooling_register);
 /**
  * cpufreq_cooling_unregister - function to remove cpufreq cooling device.
  * @cdev: thermal cooling device pointer.
+ *
+ * This interface function unregisters the "thermal-cpufreq-%x" cooling device.
  */
 void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
 {