dt-bindings: rng: apm,x-gene-rng: convert APM RNG to dtschema

Convert the APM X-Gene 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/20211227183251.132525-1-krzysztof.kozlowski@canonical.com

Documentation/devicetree/bindings/rng/apm,rng.txt

-APM X-Gene SoC random number generator.
-
-Required properties:
-
-- compatible  : should be "apm,xgene-rng"
-- reg         : specifies base physical address and size of the registers map
-- clocks      : phandle to clock-controller plus clock-specifier pair
-- interrupts  : specify the fault interrupt for the RNG device
-
-Example:
-
-	rng: rng@10520000 {
-		compatible = "apm,xgene-rng";
-		reg = <0x0 0x10520000 0x0 0x100>;
-		interrupts =   <0x0 0x41 0x4>;
-		clocks = <&rngpkaclk 0>;
-	};

Documentation/devicetree/bindings/rng/apm,x-gene-rng.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/rng/apm,x-gene-rng.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: APM X-Gene SoC Random Number Generator
+
+maintainers:
+  - Khuong Dinh <khuong@os.amperecomputing.com>
+
+properties:
+  compatible:
+    const: apm,xgene-rng
+
+  clocks:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - clocks
+  - interrupts
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        rng@10520000 {
+            compatible = "apm,xgene-rng";
+            reg = <0x0 0x10520000 0x0 0x100>;
+            interrupts = <GIC_SPI 65 IRQ_TYPE_LEVEL_HIGH>;
+            clocks = <&rngpkaclk 0>;
+        };
+    };