ACPI enabled platforms do not have a mean of regulators. Instead we use
hard coded voltage value for reference pin. When value is 0 (default) we
fall back to request a regulator.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NJonathan Cameron <Jonathan.Cameron@huawei.com>