[media] af9033: implement DVBv5 stat block counters

Implement following API commands:
DTV_STAT_ERROR_BLOCK_COUNT
DTV_STAT_TOTAL_BLOCK_COUNT

These returns total and uncorrected error packets from outer FEC.

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