dt-bindings: Add MPQ8785 voltage regulator device

Monolithic Power Systems, Inc. (MPS) synchronous step-down converter.
Signed-off-by: Charles Hsu <ythsu0511@gmail.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240131074822.2962078-1-ythsu0511@gmail.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/devicetree/bindings/trivial-devices.yaml

@@ -129,6 +129,8 @@ properties:
           - mps,mp2975
             # Monolithic Power Systems Inc. multi-phase hot-swap controller mp5990
           - mps,mp5990
+            # Monolithic Power Systems Inc. synchronous step-down converter mpq8785
+          - mps,mpq8785
             # Honeywell Humidicon HIH-6130 humidity/temperature sensor
           - honeywell,hi6130
             # IBM Common Form Factor Power Supply Versions (all versions)