dt-bindings: arm: Convert Calxeda L2 cache controller to json-schema

Convert the L2-ECC controller binding to DT schema format using
json-schema.
This is indented to be just used for error reporting.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/arm/calxeda/l2ecc.txt

-Calxeda Highbank L2 cache ECC
-
-Properties:
-- compatible : Should be "calxeda,hb-sregs-l2-ecc"
-- reg : Address and size for ECC error interrupt clear registers.
-- interrupts : Should be single bit error interrupt, then double bit error
-	interrupt.
-
-Example:
-
-	sregs@fff3c200 {
-		compatible = "calxeda,hb-sregs-l2-ecc";
-		reg = <0xfff3c200 0x100>;
-		interrupts = <0 71 4  0 72 4>;
-	};

Documentation/devicetree/bindings/arm/calxeda/l2ecc.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arm/calxeda/l2ecc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Calxeda Highbank L2 cache ECC
+
+description: |
+  Binding for the Calxeda Highbank L2 cache controller ECC device.
+  This does not cover the actual L2 cache controller control registers,
+  but just the error reporting functionality.
+
+maintainers:
+  - Andre Przywara <andre.przywara@arm.com>
+
+properties:
+  compatible:
+    const: "calxeda,hb-sregs-l2-ecc"
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    items:
+      - description: single bit error interrupt
+      - description: double bit error interrupt
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    sregs@fff3c200 {
+        compatible = "calxeda,hb-sregs-l2-ecc";
+        reg = <0xfff3c200 0x100>;
+        interrupts = <0 71 4>, <0 72 4>;
+    };