ACPICA: Update version to 20160831

ACPICA commit 3c8c04c2e8a371018b3a29f5cfe27a241caea48d

Version 20160831

Link: https://github.com/acpica/acpica/commit/3c8c04c2


Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>