arm64: dts: qcom: sc8280xp-x13s: Drop duplicate DMIC supplies

arm64: dts: qcom: sc8280xp-x13s: Drop duplicate DMIC supplies

The WCD938x codec provides two controls for each of the MIC_BIASn outputs:

 - "MIC BIASn" enables an internal regulator to generate the output
   with a configurable voltage (qcom,micbiasN-microvolt).

 - "VA MIC BIASn" enables "pull-up mode" that bypasses the internal
   regulator and directly outputs fixed 1.8V from the VDD_PX pin.
   This is intended for low-power VA (voice activation) use cases.

The audio-routing setup for the ThinkPad X13s currently specifies both
as power supplies for the DMICs, but only one of them can be active
at the same time. In practice, only the internal regulator is used
with the current setup because the driver prefers it over pull-up mode.

Make this more clear by dropping the redundant routes to the pull-up
"VA MIC BIASn" supply. There is no functional difference except that we
skip briefly switching to pull-up mode when shutting down the microphone.

Fixes: 2e498f35c385 ("arm64: dts: qcom: sc8280xp-x13s: fix va dmic dai links and routing")
Signed-off-by: Stephan Gerhold <stephan.gerhold@linaro.org>
Link: https://lore.kernel.org/r/20241203-x1e80100-va-mic-bias-v1-1-0dfd4d9b492c@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>