ACPI / PMIC: support PMIC operation region for XPower AXP288

The Baytrail-T-CR platform firmware has defined two customized operation
regions for PMIC chip Dollar Cove XPower - one is for power resource
handling and one is for thermal just like the CrystalCove one. This patch
adds support for them on top of the common PMIC opregion region code.

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Lee Jones <lee.jones@linaro.org> for the MFD part
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>