thermal_of_cooling_device_register() and thermal_cooling_device_register()
are typically called from driver probe functions, and
thermal_cooling_device_unregister() is called from remove functions. This
makes both a perfect candidate for device managed functions.

Introduce devm_thermal_of_cooling_device_register(). This function can
also be used to replace thermal_cooling_device_register() by passing a NULL
pointer as device node. The new function requires both struct device *
and struct device_node * as parameters since the struct device_node *
parameter is not always identical to dev->of_node.

Don't introduce a device managed remove function since it is not needed
at this point.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>