V4L/DVB (11992): Add missing __devexit_p()

Add missing __devexit_p() to several drivers. Also add a few missing
__init, __devinit and __exit markers. These errors could result in
build failures depending on the kernel configuration.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>