[media] Fix CI code for NetUP Dual DVB-T/C CI RF card

CI reset takes several seconds on some CAM,
so there is no need to lock mutex all that time.
Also we need not to preserve CI's reset bits in
CIBUSCTRL register, they are handled automatically by FPGA.
Set it to 0 explicitly in order to not reset wrong CAM.

Signed-off-by: Abylay Ospan <aospan@netup.ru>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>