conf: Remove non-existent SPDIF output on Dell AE515

alsa-project/alsa-lib pull request #124 was opened from drjhe:

The Dell Professional Sound Bar AE515 shows up in GNOME Settings with a digital output that doesn't physically exist. Add it to the list to suppress this.

Request URL : https://github.com/alsa-project/alsa-lib/pull/124 Patch URL : https://github.com/alsa-project/alsa-lib/pull/124.patch Repository URL: https://github.com/alsa-project/alsa-lib