ucm2: Arduino Monza: fix headset microphone capture

[GitHub pull_request - opened <github@alsa-project.org>]

alsa-project/alsa-ucm-conf pull request #901 was opened from ricardosalveti:

Capture from the Headset device on the Arduino VENTUNO Q returns only silence: its enable sequence aborts before the ADC mixers are set up, because the card has no 'Headset Mic Switch' control:

  unable to execute cset 'name='Headset Mic Switch' on'

The qcs8275 sound card only has per-input pin switches for this codec, such as 'Headset Mic12' and 'Headset Mic56'.

Dropping that line alone is not enough, as the device feeds the ADC mixers from MIC2, which the shared max98090 enable sequence routes to IN3/IN4 ('MIC2 Mux' IN34). On the VENTUNO Q those pins are not connected. The headset jack of the UNO Media Carrier goes to IN1/IN2 of the MAX98091 (MIC_IN1_IN2 to JMISC_AUDIO_MIC_IN in the ABX00181 schematics), which the device already selects with 'MIC1 Mux' IN12 and the 'Headset Mic12' pin, matching the IN12 and MICBIAS routes of the device tree. With MIC1 left out of every enabled path, DAPM also keeps MICBIAS off, so the headset microphone is not biased either.

Drop the non-existent switch and feed the ADC mixers from MIC1.

Tested on the VENTUNO Q with the UNO Media Carrier and a CTIA headset: the Headset device enables without errors, MICBIAS is on, and speech recorded from it plays back clearly on the Headphones device.

Request URL   : https://github.com/alsa-project/alsa-ucm-conf/pull/901
Patch URL     : https://github.com/alsa-project/alsa-ucm-conf/pull/901.patch
Repository URL: https://github.com/alsa-project/alsa-ucm-conf