Settings: Do not disable "Brightness control" setting

It's really annoying to have to back out of this screen when disabling
auto brightness and go back in just to enable this setting.

Change-Id: Iafc217bbad52ac9e3899fb73082e1cf8d825579a
Signed-off-by: Roman Birg <roman@cyngn.com>
Merge branch 'cm-11.0' of https://github.com/temasek/android_packages_apps_Settings into HEAD