ACPICA: ACPI 6.6: Add _VDM (Voltage Domain) object

ACPICA: ACPI 6.6: Add _VDM (Voltage Domain) object

A processor voltage domain is an identifier that specifies the voltage
plane associated with a given group of processors.

Refer to section 6.2.10. _VDM (Voltage Domain) of ACPI 6.6 specification
for more information.

Link: https://github.com/acpica/acpica/commit/d0dbb157646d
Signed-off-by: Pawel Chmielewski <pawel.chmielewski@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/1921526.atdPhlSkOF@rafael.j.wysocki