dt-bindings: arm: rockchip: add FriendlyElec NanoPi M5 board

Add device tree documentation for rk3576-nanopi-m5

Signed-off-by: John Clark <inindev@gmail.com>
Acked-by: "Rob Herring (Arm)" <robh@kernel.org>
Link: https://lore.kernel.org/r/20250628143229.74460-2-inindev@gmail.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

Author: inindev

Documentation/devicetree/bindings/arm/rockchip.yaml

@@ -300,6 +300,12 @@ properties:
               - friendlyarm,nanopi-r4s-enterprise
           - const: rockchip,rk3399
 
+      - description: FriendlyElec NanoPi M5 series boards
+        items:
+          - enum:
+              - friendlyarm,nanopi-m5
+          - const: rockchip,rk3576
+
       - description: FriendlyElec NanoPi R5 series boards
         items:
           - enum: