dt-bindings: arm: rockchip: Add Cool Pi 4B

Add Cool Pi 4B, a SBC powered by RK3588S
Signed-off-by: Andy Yan <andyshrk@163.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20231212124237.1897378-1-andyshrk@163.comSigned-off-by: Heiko Stuebner <heiko@sntech.de>

Documentation/devicetree/bindings/arm/rockchip.yaml

@@ -97,6 +97,11 @@ properties:
           - const: chipspark,rayeager-px2
           - const: rockchip,rk3066a
 
+      - description: Cool Pi 4 Model B
+        items:
+          - const: coolpi,pi-4b
+          - const: rockchip,rk3588s
+
       - description: Edgeble Neural Compute Module 2(Neu2) SoM based boards
         items:
           - const: edgeble,neural-compute-module-2-io   # Edgeble Neural Compute Module 2 IO Board