Set brightness_switch_enabled to 0

This change sets acpi/video's brightness_switch_enabled boolean to 0,
basically disabling the video driver from adjusting screen brightness
on its own. This was causing discrepancies between the kernel and the
Android framework, causing unwanted behaviour like brightness bursts
when changing levels with the keyboard, and allowing the user to lower
the brightness level below the framework's imposed minimum value.

The brightness keys will still work, as they change the screen
backlight's brightness value, which is monitored by the framework.

Issue: APDEV-1867

Change-Id: I4e7cd35b60f634fa100401c19ef02d2125f6abb6
Signed-off-by: Tiberiu Breana <tiberiu.a.breana@intel.com>
Reviewed-on: https://android.intel.com/178071
Reviewed-by: Suman, Viorel <viorel.suman@intel.com>
Tested-by: Vlaescu, CristianX <cristianx.vlaescu@intel.com>
Reviewed-by: Chiras, Robert <robert.chiras@intel.com>