dt-bindings: display/msm: Document the DPU for X1E80100

Document the DPU for Qualcomm X1E80100 platform in the SM8650 schema, as
they are similar.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/579072/
Link: https://lore.kernel.org/r/20240220-x1e80100-display-v4-1-971afd9de861@linaro.org


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