ucm2/conf.d: add symlink for Qualcomm DB820c

ucm2/conf.d: add symlink for Qualcomm DB820c

Since the release 6.3 Linux kernel uses driver name apq8096 for Qualcomm
Dragonboard 820c. This makes alsaucm look for conf.d/apq8096/DB820c.conf
and then for conf.d/apq8096/apq8096.conf, while alsa-ucm-conf has
historical conf.d/DB820c/DB820c.conf symlink. Add symlink to provide
correct configuration for the device.

Closes: https://github.com/alsa-project/alsa-ucm-conf/pull/428
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>