SG2042 use an external MCU to provide basic hardware information
and thermal sensors.

Add driver support for the onboard MCU of SG2042.
Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
Message-ID: <IA1PR20MB49536C786048D1E676BB9C20BB822@IA1PR20MB4953.namprd20.prod.outlook.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>