mfd: Add support for Cherry Trail Dollar Cove TI PMIC

This patch adds the MFD driver for Dollar Cove (TI version) PMIC with
ACPI INT33F5 that is found on some Intel Cherry Trail devices.
The driver is based on the original work by Intel, found at:
  https://github.com/01org/ProductionKernelQuilts

This is a minimal version for adding the basic resources.  Currently,
only ACPI PMIC opregion and the external power-button are used.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=193891



Signed-off-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>