[ALSA] add CMI8788 driver

Add the snd-oxygen driver for the C-Media CMI8788 (Oxygen) chip, used on
the Asound A-8788, AuzenTech X-Meridian, Bgears b-Enspirer,
Club3D Theatron DTS, HT-Omega Claro, Razer Barracuda AC-1,
Sondigo Inferno, and TempoTec HIFIER sound cards.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>