Backport → v2022-updates: d/patches: Add fallback sink script
When running PW/WP on board with only HDMI audio output, and this one is not connected, PW fails to create the Dummy Output as policy endpoint are created by WP.
https://phabricator.apertis.org/T8516
Signed-off-by: Frédéric Danis frederic.danis@collabora.com