Make lights wrapper opt-in

* Don't build in by default.
* Plan is to switch all devices to an open HAL eventually,
  but until that is done, this can stay while we move
  devices, starting with 8974s.

Change-Id: I9c198714c5cb438f4dc8a7f78c47947aa1769ad6
Merge remote-tracking branch 'cm/cm-12.0' into cm-12.0