dt-bindings: arm: hisilicon: convert hisilicon,cpuctrl bindings to json-schema

Convert the Hisilicon CPU controller binding to DT schema format using
json-schema.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20200929141454.2312-12-thunder.leizhen@huawei.comSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/arm/hisilicon/controller/cpuctrl.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arm/hisilicon/controller/cpuctrl.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Hisilicon CPU controller
+
+maintainers:
+  - Wei Xu <xuwei5@hisilicon.com>
+
+description: |
+  The clock registers and power registers of secondary cores are defined
+  in CPU controller, especially in HIX5HD2 SoC.
+
+properties:
+  compatible:
+    items:
+      - const: hisilicon,cpuctrl
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+...

Documentation/devicetree/bindings/arm/hisilicon/controller/hisilicon,cpuctrl.txt

-Hisilicon CPU controller
-
-Required properties:
-- compatible : "hisilicon,cpuctrl"
-- reg : Register address and size
-
-The clock registers and power registers of secondary cores are defined
-in CPU controller, especially in HIX5HD2 SoC.