dt-bindings: input: max77650: convert the binding document to yaml

Convert the binding document for MAX77650 onkey module to YAML.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/input/max77650-onkey.txt

-Onkey driver for MAX77650 PMIC from Maxim Integrated.
-
-This module is part of the MAX77650 MFD device. For more details
-see Documentation/devicetree/bindings/mfd/max77650.txt.
-
-The onkey controller is represented as a sub-node of the PMIC node on
-the device tree.
-
-Required properties:
---------------------
-- compatible:		Must be "maxim,max77650-onkey".
-
-Optional properties:
-- linux,code:		The key-code to be reported when the key is pressed.
-			Defaults to KEY_POWER.
-- maxim,onkey-slide:	The system's button is a slide switch, not the default
-			push button.
-
-Example:
---------
-
-	onkey {
-		compatible = "maxim,max77650-onkey";
-		linux,code = <KEY_END>;
-		maxim,onkey-slide;
-	};

Documentation/devicetree/bindings/input/max77650-onkey.yaml

+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/max77650-onkey.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Onkey driver for MAX77650 PMIC from Maxim Integrated.
+
+maintainers:
+  - Bartosz Golaszewski <bgolaszewski@baylibre.com>
+
+description: |
+  This module is part of the MAX77650 MFD device. For more details
+  see Documentation/devicetree/bindings/mfd/max77650.yaml.
+
+  The onkey controller is represented as a sub-node of the PMIC node on
+  the device tree.
+
+properties:
+  compatible:
+    const: maxim,max77650-onkey
+
+  linux,code:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      The key-code to be reported when the key is pressed. Defaults
+      to KEY_POWER.
+
+  maxim,onkey-slide:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      The system's button is a slide switch, not the default push button.
+
+required:
+  - compatible