dt-bindings: rng: nuvoton,npcm-rng: convert Nuvoton NPCM RNG to dtschema

Convert the Nuvoton NPCM RNG bindings to DT schema.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211227183251.132525-5-krzysztof.kozlowski@canonical.com

Documentation/devicetree/bindings/rng/nuvoton,npcm-rng.txt

-NPCM SoC Random Number Generator
-
-Required properties:
-- compatible  : "nuvoton,npcm750-rng" for the NPCM7XX BMC.
-- reg         : Specifies physical base address and size of the registers.
-
-Example:
-
-rng: rng@f000b000 {
-	compatible = "nuvoton,npcm750-rng";
-	reg = <0xf000b000 0x8>;
-};

Documentation/devicetree/bindings/rng/nuvoton,npcm-rng.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/rng/nuvoton,npcm-rng.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Nuvoton NPCM SoC Random Number Generator
+
+maintainers:
+  - Avi Fishman <avifishman70@gmail.com>
+  - Tomer Maimon <tmaimon77@gmail.com>
+  - Tali Perry <tali.perry1@gmail.com>
+  - Patrick Venture <venture@google.com>
+  - Nancy Yuen <yuenn@google.com>
+  - Benjamin Fair <benjaminfair@google.com>
+
+properties:
+  compatible:
+    const: nuvoton,npcm750-rng
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    rng@f000b000 {
+        compatible = "nuvoton,npcm750-rng";
+        reg = <0xf000b000 0x8>;
+    };