Most new Qualcomm WCD codecs support MBHC(Multi Button Headset Control) via ADC.

This patchset adds support to Common parts of this MBHC support so that
WCD codecs need not duplicate them. To do that codec exposes set of
register fields and callbacks to this common driver to control it.
Signed-off-by: NSrinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20210604115230.23259-3-srinivas.kandagatla@linaro.orgSigned-off-by: NMark Brown <broonie@kernel.org>