dt-bindings: gpu: mali-bifrost: Add RK3568 compatible

The Rockchip RK3568 SoC has a Bifrost Mali-G52 GPU,
add a compatible string for it.
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Link: https://lore.kernel.org/r/20210805025948.10900-3-ezequiel@collabora.comSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/gpu/arm,mali-bifrost.yaml

@@ -20,6 +20,7 @@ properties:
           - mediatek,mt8183-mali
           - realtek,rtd1619-mali
           - rockchip,px30-mali
+          - rockchip,rk3568-mali
       - const: arm,mali-bifrost # Mali Bifrost GPU model/revision is fully discoverable
 
   reg: