only call ecore_x_randr_output_backlight_available() once in backlight
only call ecore_x_randr_output_backlight_available() once in backlight

tasn/enlightenment,tasn/enlightenment,rvandegrift/e,tizenorg/platform.upstream.enlightenment,FlorentRevest/Enlightenment,rvandegrift/e,FlorentRevest/Enlightenment,rvandegrift/e,FlorentRevest/Enlightenment,tizenorg/platform.upstream.enlightenment,tasn/enlightenment,tizenorg/platform.upstream.enlightenment