ACPI / PMIC: Add TI PMIC TPS68470 operation region driver

The Kabylake platform coreboot (Chrome OS equivalent of
BIOS) has defined 4 operation regions for the TI TPS68470 PMIC.
These operation regions are to enable/disable voltage
regulators, configure voltage regulators, enable/disable
clocks and to configure clocks.

This config adds ACPI operation region support for TI TPS68470 PMIC.
TPS68470 device is an advanced power management unit that powers
a Compact Camera Module (CCM), generates clocks for image sensors,
drives a dual LED for flash and incorporates two LED drivers for
general purpose indicators.

This driver enables ACPI operation region support to control voltage
regulators and clocks for the TPS68470 PMIC.

Signed-off-by: Rajmohan Mani <rajmohan.mani@intel.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>