Revert "Add Button Backlight control (1/2)"

This reverts commit 75ce2676aa3c794e53ff0b7989dccfb328acff8a.

Change-Id: Iffef2dfbdbd4846d5e5bff871642b476b16c8012
Merge remote-tracking branch 'upstream/android-4.4' into android-4.4