V4L/DVB: cx22702: Avoid duplicating code in branches

Calling the same functions in if/else or switch/case branches is
inefficient. Refactor the code for a smaller binary and increased
readability.

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