regulator: dt-bindings: Add ADI MAX77503 support

Add ADI MAX77503 buck converter devicetree document.
Signed-off-by: Gokhan Celik <gokhan.celik@analog.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/fb2cb32219eb1a5f85169d6c85cd2c057c5bb4a9.1698000185.git.gokhan.celik@analog.comSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/regulator/adi,max77503-regulator.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright (c) 2023 Analog Devices, Inc.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/regulator/adi,max77503-regulator.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices MAX77503 Buck Converter
+
+maintainers:
+  - Gokhan Celik <Gokhan.Celik@analog.com>
+
+description: |
+  The Analog Devices MAX77503 is a single channel 14V input, 1.5A
+  high-efficiency buck converter. This converter has 94% efficiency
+  for 2-Cell/3-Cell battery applications.
+
+allOf:
+  - $ref: regulator.yaml#
+
+properties:
+  compatible:
+    enum:
+      - adi,max77503
+
+  reg:
+    description: I2C address of the device
+    items:
+      - enum: [0x1e, 0x24, 0x37]
+
+required:
+  - compatible
+  - reg
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        regulator@1e {
+            compatible = "adi,max77503";
+            reg = <0x1e>;
+
+            regulator-min-microvolt = <800000>;
+            regulator-max-microvolt = <5000000>;
+        };
+    };