dt-bindings: hwmon: Add mps mp5990 driver bindings

Add a device tree bindings for mp5990 device.

Signed-off-by: Peter Yin <peteryin.openbmc@gmail.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20231113155008.2147090-2-peteryin.openbmc@gmail.com


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