dt-bindings: display/msm: add support for the display on SM8450

Add DPU and MDSS schemas to describe MDSS and DPU blocks on the Qualcomm
SM8450 platform.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/514234/
Link: https://lore.kernel.org/r/20221207012231.112059-5-dmitry.baryshkov@linaro.org


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>