sepolicy: Move display color_service to private

- Move display snapdragon color_service to sepolicy/private.
- Rules to access color_service from private and system app are
  also moved to private. Above changes are done as part of
  O-MR1 requirement.
- Permissions for 'packpattern' sysfs node added.

Change-Id: I45ef10805b6ff41c328cb75160ddd94772ee97ef