arm64: dts: qcom: sc8280xp-x13s: drop sound-dai-cells from eDisplayPort

arm64: dts: qcom: sc8280xp-x13s: drop sound-dai-cells from eDisplayPort

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

  sc8280xp-lenovo-thinkpad-x13s.dtb: displayport-controller@aea0000: #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/20231107103540.27353-2-krzysztof.kozlowski@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>