dt-bindings: gpu: Add rockchip,rk3562-mali compatible

The Rockchip RK3562 GPU is ARM Mali-G52, use the same driver with
"arm,mali-bifrost". Extend the binding accordingly to allow

compatible = "rockchip,rk3562-mali", "arm,mali-bifrost";

Signed-off-by: Kever Yang <[e-mail]>
Acked-by: "Rob Herring (Arm)" <[e-mail]>
Signed-off-by: Heiko Stuebner <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

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

···
               - renesas,r9a07g044-mali
               - renesas,r9a07g054-mali
               - rockchip,px30-mali
+              - rockchip,rk3562-mali
               - rockchip,rk3568-mali
               - rockchip,rk3576-mali
           - const: arm,mali-bifrost # Mali Bifrost GPU model/revision is fully discoverable