hda: improve the microphone device allocation

[GitHub pull_request - opened]

alsa-project/alsa-ucm-conf pull request #97 was opened from perexg:

This change use the local variables for the UCM microphone
device names. Also, handle the no-dmic case for sof-hda-dsp
hardware.

Request URL   : https://github.com/alsa-project/alsa-ucm-conf/pull/97
Patch URL     : https://github.com/alsa-project/alsa-ucm-conf/pull/97.patch
Repository URL: https://github.com/alsa-project/alsa-ucm-conf