USB-Audio, Generic config file is missing

alsa-project/alsa-ucm-conf issue #353 was opened from smangels:

* the intermediate config file is missing, it is referenced in ucm2/USB-Audio/USB-Audio.conf file but wasn't in place.

Issue URL : https://github.com/alsa-project/alsa-ucm-conf/issues/353 Repository URL: https://github.com/alsa-project/alsa-ucm-conf