dt-bindings: reset: bitmain,bm1880-reset: Convert to yaml

Convert the device tree bindings for the Bitmain BM1880 reset controller
to YAML schema to allow participating in DT validation.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220407154338.4190674-4-p.zabel@pengutronix.de

Documentation/devicetree/bindings/reset/bitmain,bm1880-reset.txt

-Bitmain BM1880 SoC Reset Controller
-===================================
-
-Please also refer to reset.txt in this directory for common reset
-controller binding usage.
-
-Required properties:
-- compatible:   Should be "bitmain,bm1880-reset"
-- reg:          Offset and length of reset controller space in SCTRL.
-- #reset-cells: Must be 1.
-
-Example:
-
-        rst: reset-controller@c00 {
-                compatible = "bitmain,bm1880-reset";
-                reg = <0xc00 0x8>;
-                #reset-cells = <1>;
-        };

Documentation/devicetree/bindings/reset/bitmain,bm1880-reset.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright 2019 Manivannan Sadhasivam <mani@kernel.org>
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/reset/bitmain,bm1880-reset.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Bitmain BM1880 SoC Reset Controller
+
+maintainers:
+  - Manivannan Sadhasivam <mani@kernel.org>
+
+properties:
+  compatible:
+    const: bitmain,bm1880-reset
+
+  reg:
+    maxItems: 1
+
+  "#reset-cells":
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - "#reset-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    rst: reset-controller@c00 {
+        compatible = "bitmain,bm1880-reset";
+        reg = <0xc00 0x8>;
+        #reset-cells = <1>;
+    };