[media] af9033: wrap DVBv3 UCB to DVBv5 UCB stats

Remove 'duplicate' DVBv3 read UCB implementation and return value,
calculated already for DVBv5 statistics.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>