ASoC: nau8821: Revise MICBIAS control for power saving.

The patch helps save power by control MICBIAS. The headset's
MICBIAS should be disabled without button requirement.

Signed-off-by: Seven Lee <wtli@nuvoton.com>
Link: https://lore.kernel.org/r/20230913064003.2925997-1-wtli@nuvoton.com


Signed-off-by: Mark Brown <broonie@kernel.org>