Port the backlight selection logic to the new backlight interface
selection API.
Signed-off-by: Hans de Goede <hdegoede@redhat.com> Acked-by: Pali Rohár <pali.rohar@gmail.com> Acked-by: Darren Hart <dvhart@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>