ACPICA: Update predefined info table for _MLS method

The second object for each sub-package of the _MLS method is
defined to be a unicode Buffer object. This fixes the predefined
table where this object was incorrectly defined as a String.

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>