hwmon: Add hwmon driver for Intel MAX 10 BMC

This patch adds hwmon functionality for Intel MAX 10 BMC chip. This BMC
chip connects to a set of sensor chips to monitor current, voltage,
thermal and power of different components on board. The BMC firmware is
responsible for sensor data sampling and recording in shared registers.
Host driver reads the sensor data from these shared registers and
exposes them to users as hwmon interfaces.

Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Signed-off-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/1600669071-26235-3-git-send-email-yilun.xu@intel.com


[groeck: Adjusted subject]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>