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>
(cherry picked from commit 11982b781f586aa39c7cb98c2c139a8adcd1f2ce)

Conflicts:
	src/com/android/settings/cyanogenmod/StatusBar.java