[media] cx24120: Convert ucblocks to dvbv5 stats

DVBv3 is a legacy API. Drivers should use DVBv5, in order to support
modern applications. So, implement UCB using dvbv5.

Signed-off-by: Jemma Denson <jdenson@gmail.com>
Signed-off-by: Patrick Boettcher <patrick.boettcher@posteo.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>