ucm2: add support for "Digidesign Mbox 3"

alsa-project/alsa-ucm-conf pull request #237 was opened from ManuLinares:

Add ucm2 support for "Digidesign Mbox 3", without it, alsa detects as analog-surround4.0, instead of 2 line and 2 spdif in/out.

[alsa-info.txt](https://github.com/alsa-project/alsa-ucm-conf/files/9944813/alsa-info.txt)

Request URL : https://github.com/alsa-project/alsa-ucm-conf/pull/237 Patch URL : https://github.com/alsa-project/alsa-ucm-conf/pull/237.patch Repository URL: https://github.com/alsa-project/alsa-ucm-conf