dt-bindings: arm64: rockchip: Add Pine64 PineTab2

Add devicvetree binding documentation for Pine64 PineTab2
which uses the Rockchip RK3566 SoC.
Signed-off-by: Manuel Traut <manut@mecka.net>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240127-pinetab2-v4-3-37aab1c39194@mecka.net
[moved Pinetab below Pinephone to keep alphabetical sorting]
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

Documentation/devicetree/bindings/arm/rockchip.yaml

@@ -649,6 +649,14 @@ properties:
           - const: pine64,pinephone-pro
           - const: rockchip,rk3399
 
+      - description: Pine64 PineTab2
+        items:
+          - enum:
+              - pine64,pinetab2-v0.1
+              - pine64,pinetab2-v2.0
+          - const: pine64,pinetab2
+          - const: rockchip,rk3566
+
       - description: Pine64 Rock64
         items:
           - const: pine64,rock64