hwmon: pmbus : Add ADP1050 support

[RaduSabau1]

Add support for ADP1050 Digital Controller for Isolated Power Supplies with PMBus interface Voltage, Current and Temperature Monitor.

The ADP1050 implements several features to enable a robust system of parallel and redundant operation for customers who require high availability. The device can measure voltage, current and temperature that can be used in different techniques to identify and safely shut down an erroneous power supply in parallel operation mode.

In order for the device to read correct VIN and IIN values, scales for these measurements need to be set accordingly to the resistor divider information on the phyisical board and set in the device-tree.