arm64: dts: qcom: sm8250-pdx203: add required pin function

DT bindings expect function in each pin state in the pin configuration:

  sm8250-sony-xperia-edo-pdx203.dtb: pinctrl@f100000: cam-pwr-b-state: 'oneOf' conditional failed, one must be fixed:
    'function' is a required property

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230717210055.21979-2-krzysztof.kozlowski@linaro.org


Signed-off-by: Bjorn Andersson <andersson@kernel.org>