Add boolean ti,micbias1-gpo and ti,micbias2-gpo devicetree properties.

When set, the respective MICBIAS pins can be used as general purpose
outputs controlled via the GPIO framework, in addition to the two
configurable GPIO pins.

This is useful in applications where the MICBIAS functionality is
not required, but it is useful to have a couple of extra GPIO pins.

The voltage on the respective MICBIAS pin in the active state is
governed by the ti,micbias1-vg and ti,micbias2-vg properties,
respectively (same properties as when the pins are used as
MICBIAS pins).
Signed-off-by: Ricard Wanderlof <ricard.wanderlof@axis.com>
Link: https://msgid.link/r/20240607-tlv320adc3xxx-micbias-gpo-v3-2-59dbec8b98f4@axis.comSigned-off-by: Mark Brown <broonie@kernel.org>