media: dvb-frontends/stv0367: update UCB readout condition logic

Since the other statistics are read when fe_status conditions are TRUE,
change the ucblocks readout logic to match this aswell.

Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>