Now the manual brightness mode only applies to the LCD backlight and
button and keyboard backlights are always managed automatically.
Fixes bug b/2195798 (Passion capacitive key backlights don't always come on)
This change only affects the framework based auto-brightness implementation.
Hardware auto-brightness is not affected.
Change-Id: Ib88310d642d498591e8879c8269d630ff3f7c8af
Signed-off-by: Mike Lockwood <lockwood@android.com>