drm/msm: Add support for SM8350

Add compatibles string, "qcom,sm8350-mdss", for the multimedia display
subsystem unit used on Qualcomm SM8350 platform.

Signed-off-by: Robert Foss <robert.foss@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/516345/
Link: https://lore.kernel.org/r/20221230153554.105856-6-robert.foss@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>