dt-bindings: riscv: add Andes QiLai SoC and the Voyager board bindings

Add DT binding documentation for the Andes QiLai SoC and the
Voyager development board.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Ben Zong-You Xie <ben717@andestech.com>
Link: https://lore.kernel.org/r/20250711133025.2192404-3-ben717@andestech.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Documentation/devicetree/bindings/riscv/andes.yaml

@@ -0,0 +1,25 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/riscv/andes.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Andes SoC-based boards
+
+maintainers:
+  - Ben Zong-You Xie <ben717@andestech.com>
+
+description:
+  Andes SoC-based boards
+
+properties:
+  $nodename:
+    const: '/'
+  compatible:
+    oneOf:
+      - items:
+          - enum:
+              - andestech,voyager
+          - const: andestech,qilai
+
+additionalProperties: true