Add basic support for the Maxim Integrated MAX31722/MAX31723 SPI
temperature sensors / thermostats.

Includes:
    - ACPI support;
    - raw temperature readings;
    - power management

Datasheet:
https://datasheets.maximintegrated.com/en/ds/MAX31722-MAX31723.pdfSigned-off-by: NTiberiu Breana <tiberiu.a.breana@intel.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>