dt-bindings: hwmon: pmbus: Add bindings for MPS MP297x

dt-bindings: hwmon: pmbus: Add bindings for MPS MP297x

Remove mps297x from trivial-devices as it requires
additional properties and does not fit into the trivial
devices category.

Add new bindings for MPS mp2971, mp2973 & mp2975.
It is Dual-Loop, Digital Multi-Phase Controller with PMBUS
interface

Signed-off-by: Naresh Solanki <naresh.solanki@9elements.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Message-ID: <20241022103750.572677-1-naresh.solanki@9elements.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>