[media] saa7164: convert buffering structs to be more generic

Current structs assume transport, making a number of changes to
switch to generic functions allowing a smoother integration
for the analog encoder.

Signed-off-by: Steven Toth <stoth@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
5 files changed