arm64: dts: qcom: sc8180x-primus: drop sound-dai-cells from eDisplayPort

arm64: dts: qcom: sc8180x-primus: drop sound-dai-cells from eDisplayPort

Qualcomm MDSS Embedded DisplayPort bindings do not allow
sound-dai-cells:

  sc8180x-primus.dtb: displayport-controller@ae9a000: #sound-dai-cells: False schema does not allow [[0]]

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20231107103540.27353-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>