The cx22702 returns an 8 bit unshifted value for signal strength; this is 
inconsistent with most other frontends
Signed-off-by: NBradley Derek Kite <bradley.kite@gmail.com>
Signed-off-by: NAndrew de Quincey <adq_dvb@lidskialf.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>