dt-bindings: display/msm: Add SM6125 MDSS

Document the SM6125 MDSS.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Patchwork: https://patchwork.freedesktop.org/patch/548976/
Link: https://lore.kernel.org/r/20230723-sm6125-dpu-v4-9-a3f287dd6c07@somainline.org


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