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: acpica/acpica@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

Author: pawelchm-intel

drivers/acpi/acpica/acpredef.h

@@ -587,6 +587,9 @@ const union acpi_predefined_info acpi_gbl_predefined_methods[] = {
 	  METHOD_RETURNS(ACPI_RTYPE_PACKAGE)}},	/* Variable-length (Pkgs) each (var Ints) */
 	PACKAGE_INFO(ACPI_PTYPE2_MIN, ACPI_RTYPE_INTEGER, 5, 0, 0, 0),
 
+	{{"_VDM", METHOD_0ARGS,
+	  METHOD_RETURNS(ACPI_RTYPE_INTEGER)}},
+
 	{{"_HRV", METHOD_0ARGS,
 	  METHOD_RETURNS(ACPI_RTYPE_INTEGER)}},