[media] lmedm04: implement dvb v5 statistics

Indroduce function lme2510_update_stats to update
statistics directly from usb interrupt.

Provide signal and snr wrap rounds for dvb v3 functions.

Block and post bit are not available.

When i2c_talk_onoff is on no statistics are available,
with possible future hand over to the relevant frontend/tuner.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>