hwmon: (pmbus) Add driver for Infineon IR36021

The IR36021 is a dual‐loop digital multi‐phase buck controller.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Link: https://lore.kernel.org/r/20210301035954.16713-3-chris.packham@alliedtelesis.co.nz


Signed-off-by: Guenter Roeck <linux@roeck-us.net>