V4L/DVB (9071): S2API: Implement result codes for individual commands

This allows application developers to determine which particular
command in a sequence is invalid, or failing with error.

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