replace millivolt with correct microvolt and adjust value to
the minimal value allowed by documentation.

Found with `make qcom/sdm845-oneplus-fajita.dtb`.

Fixes:
arch/arm64/boot/dts/qcom/sdm845-oneplus-fajita.dt.yaml: codec@1: 'qcom,micbias1-microvolt' is a required property
        From schema: Documentation/devicetree/bindings/sound/qcom,wcd934x.yaml
arch/arm64/boot/dts/qcom/sdm845-oneplus-fajita.dt.yaml: codec@1: 'qcom,micbias2-microvolt' is a required property
        From schema: Documentation/devicetree/bindings/sound/qcom,wcd934x.yaml
arch/arm64/boot/dts/qcom/sdm845-oneplus-fajita.dt.yaml: codec@1: 'qcom,micbias3-microvolt' is a required property
        From schema: Documentation/devicetree/bindings/sound/qcom,wcd934x.yaml
arch/arm64/boot/dts/qcom/sdm845-oneplus-fajita.dt.yaml: codec@1: 'qcom,micbias4-microvolt' is a required property
        From schema: Documentation/devicetree/bindings/sound/qcom,wcd934x.yaml
arch/arm64/boot/dts/qcom/sdm845-oneplus-fajita.dt.yaml: codec@1: 'qcom,micbias1-millivolt', 'qcom,micbias2-millivolt', 'qcom,micbias3-millivolt', 'qcom,micbias4-millivolt' do not match any of the regexes: '^.*@[0-9a-f]+$', 'pinctrl-[0-9]+'

Fixes: 27ca1de0 ("arm64: dts: qcom: sdm845: add slimbus nodes")
Signed-off-by: David Heidelberg <david@ixit.cz>
Tested-by: Steev Klimaszewski <steev@kali.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211213195105.114596-1-david@ixit.cz