ACPICA: Predefined names: Add support for the _PRP method.

This is not an official predefined name yet, but we add it to assist
with development.

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>