In order to properly bias headset microphones, there should be a pull-up
resistor between pins HBIAS and MIC2P. This can be an external resistor,
but the codec also provides an internal 2.2K resistor which is enabled
by a register.

This patch enables or disables the internal bias resistor based on a
device tree property.
Signed-off-by: Arnaud Ferraris <arnaud.ferraris@collabora.com>
[Samuel: split binding and implementation; move to device probe]
Signed-off-by: Samuel Holland <samuel@sholland.org>
Link: https://lore.kernel.org/r/20220621035452.60272-3-samuel@sholland.orgSigned-off-by: Mark Brown <broonie@kernel.org>