N900 audio recording needs that codec provides bias voltage for integrated
digital microphone and headset microphone depending which one is used.
Digital microphone uses 2 V bias and it comes from the codec A part. Codec
B part drives the headset microphone bias and that is set to 2.5 V.

Cc: stable@vger.kernel.org # v3.16+
Signed-off-by: Pavel Machek <pavel@ucw.cz>
[Jarkko: Headset mic bias changed to 2 (2.5 V) as it was before commit
e2e8bfdf ("ASoC: tlv320aic3x: Convert mic bias to a supply widget")]
Signed-off-by: Jarkko Nikula <jarkko.nikula@bitmer.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>