V4L/DVB: cx18: make it so cx18-alsa-main.c compiles

Fix some basic compilation issues with Andy's original code.  In particular,
temporarily #ifdef out the mixer code, add some additional exception handling,
fix a couple of typos, and add a copyright line.

This work was sponsored by ONELAN Limited.

Signed-off-by: Devin Heitmueller <dheitmueller@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>