dt-bindings: display/msm: qcom,sa8775p-mdss: fix the example

dt-bindings: display/msm: qcom,sa8775p-mdss: fix the example

Add p1 region to the list of DP registers in the SA8775p example. This
fixes the following warning:

Documentation/devicetree/bindings/display/msm/qcom,sa8775p-mdss.example.dtb: displayport-controller@af54000: reg: [[183844864, 260], [183845376, 192], [183848960, 1904], [183853056, 156]] is too short

Fixes: 409685915f00 ("dt-bindings: display/msm: Document MDSS on SA8775P")
Reported-by: Rob Herring <robh@kernel.org>
Closes: https://lore.kernel.org/dri-devel/CAL_JsqJ0zoyaZAgZtyJ8xMsPY+YzrbF-YG1vPN6tFoFXQaW09w@mail.gmail.com/
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Patchwork: https://patchwork.freedesktop.org/patch/624068/
Link: https://lore.kernel.org/r/20241112-fd-dp-fux-warning-v2-1-8cc4960094bd@linaro.org
Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>