dt-bindings: gpu: Add rockchip,rk3576-mali compatible

The rk3576 SoC has an ARM Mali G52 MC3 GPU, that is compatible with
arm,mali-bifrost.

Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20240903152308.13565-6-detlev.casanova@collabora.com