dt-bindings: rockchip: Add BananaPi R2 Pro Board

Add Devicetree Binding for Bananapi R2 Pro Board based on rk3568 SoC
Co-developed-by: Peter Geis <pgwipeout@gmail.com>
Signed-off-by: Peter Geis <pgwipeout@gmail.com>
Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220123135116.136846-2-linux@fw-web.deSigned-off-by: Heiko Stuebner <heiko@sntech.de>

Documentation/devicetree/bindings/arm/rockchip.yaml

@@ -651,6 +651,11 @@ properties:
           - const: rockchip,rk3568-evb1-v10
           - const: rockchip,rk3568
 
+      - description: Rockchip RK3568 Banana Pi R2 Pro
+        items:
+          - const: rockchip,rk3568-bpi-r2pro
+          - const: rockchip,rk3568
+
 additionalProperties: true
 
 ...