dt-bindings: display/msm: add support for the display on SM8250

Add DPU and MDSS schemas to describe MDSS and DPU blocks on the Qualcomm
SM8250 platform.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/508397/
Link: https://lore.kernel.org/r/20221024164225.3236654-13-dmitry.baryshkov@linaro.org


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