dt-bindings: display/msm: dp-controller: add X1E80100

dt-bindings: display/msm: dp-controller: add X1E80100

Add X1E80100 to the dp-controller bindings, it has DisplayPort
controller similar to other platforms, but it uses its own compatible
string.

Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/672578/
Link: https://lore.kernel.org/r/20250903-dp_mst_bindings-v8-5-7526f0311eaa@oss.qualcomm.com