dt-bindings: display/msm/gpu: Allow A7xx SKUs

Allow A7xx SKUs, such as the A730 GPU found on SM8450 and friends.
They use GMU for all things DVFS, just like most A6xx GPUs.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD
Tested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> # sm8450
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/559281/


Signed-off-by: Rob Clark <robdclark@chromium.org>