Add support for mp5990 device from Monolithic Power Systems, Inc. (MPS)
vendor. This is a Hot-Swap Controller.
Signed-off-by: Peter Yin <peteryin.openbmc@gmail.com>
Link: https://lore.kernel.org/r/20231113155008.2147090-3-peteryin.openbmc@gmail.com
[groeck: Improved and clarified comments]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>