thermal: add a warning for temperature emulation feature

Because this feature is for debuging purposes, it is highly
recommended to do not enable this on production systems.
This patch adds warnings for system integrators, so that
people are aware of this potential security issue.

Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

Documentation/thermal/sysfs-api.txt

@@ -265,6 +265,10 @@ emul_temp
 	Unit: millidegree Celsius
 	WO, Optional
 
+	  WARNING: Be careful while enabling this option on production systems,
+	  because userland can easily disable the thermal policy by simply
+	  flooding this sysfs node with low temperature values.
+
 *****************************
 * Cooling device attributes *
 *****************************

drivers/thermal/Kconfig

@@ -86,6 +86,10 @@ config THERMAL_EMULATION
 	  user can manually input temperature and test the different trip
 	  threshold behaviour for simulation purpose.
 
+	  WARNING: Be careful while enabling this option on production systems,
+	  because userland can easily disable the thermal policy by simply
+	  flooding this sysfs node with low temperature values.
+
 config SPEAR_THERMAL
 	bool "SPEAr thermal sensor driver"
 	depends on PLAT_SPEAR