media: cx231xx: Add support for Dexatek USB Video Grabber 1d19:6108

media: cx231xx: Add support for Dexatek USB Video Grabber 1d19:6108

Add Dexatek Technology Ltd USB Video Grabber 1d19:6108 to the cx231xx
driver. This device is sold under the name "BAUHN DVD Maker (DK8723)" by
ALDI in Australia.

This device is similar to 1d19:6109, which is already included in cx231xx.

Both video and audio capture function correctly after installing the
patched cx231xx driver.

Patch Changelog
v1:
 - Initial submission.
v2:
 - Fix SoB + Improve subject.
v3:
 - Rephrase message to not exceed 75 characters per line.
 - Removed reference to external GitHub URL.

Signed-off-by: Rohan Barar <rohan.barar@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>