ACPICA: Update comments about behavior when _STA does not exist
No functional change. Add some comments concerning behavior
when the _STA method does not exist. According to the ACPI
specification, in this case the device should be assumed to be
present, functional, and enabled.
Signed-off-by: Bob Moore <robert.moore@intel.com> Signed-off-by: Lv Zheng <lv.zheng@intel.com> Acked-by: Len Brown <len.brown@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>