[media] DVB: return meaningful error codes in dvb_frontend

- Return values should not be ORed. Abort early instead.
- Return -EINVAL instead of -1.

Signed-off-by: Andreas Oberritter <obi@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
1 file changed