dt-bindings: rng: Add StarFive TRNG module

Add documentation to describe Starfive true random number generator
module.
Co-developed-by: Jenny Zhang <jenny.zhang@starfivetech.com>
Signed-off-by: Jenny Zhang <jenny.zhang@starfivetech.com>
Signed-off-by: Jia Jie Ho <jiajie.ho@starfivetech.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/rng/starfive,jh7110-trng.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: StarFive SoC TRNG Module
+
+maintainers:
+  - Jia Jie Ho <jiajie.ho@starfivetech.com>
+
+properties:
+  compatible:
+    const: starfive,jh7110-trng
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: Hardware reference clock
+      - description: AHB reference clock
+
+  clock-names:
+    items:
+      - const: hclk
+      - const: ahb
+
+  resets:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - resets
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    rng: rng@1600C000 {
+        compatible = "starfive,jh7110-trng";
+        reg = <0x1600C000 0x4000>;
+        clocks = <&clk 15>, <&clk 16>;
+        clock-names = "hclk", "ahb";
+        resets = <&reset 3>;
+        interrupts = <30>;
+    };
+...