dt-bindings: display/msm: dsi-controller-main: add SC8180X

dt-bindings: display/msm: dsi-controller-main: add SC8180X

Describe the SC8180X-specific compatible for the DSI controller persent
on the SoC. While the current DT for SC8180X doesn't use this
compatible, all other platforms were updated to have one. This change
makes SC8180X follow the lead.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Patchwork: https://patchwork.freedesktop.org/patch/662495/
Link: https://lore.kernel.org/r/20250704-mdss-schema-v1-1-e978e4e73e14@oss.qualcomm.com