V4L/DVB (5319): Set tda827x to sleep mode after attach

This change sets the tda827x to sleep mode right after attach in dvb
mode. It is just to save power. For the same reason, the ADC of the
tda10046 gets turned off in sleep mode.

Signed-off-by: Hartmut Hackmann <hartmut.hackmann@t-online.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>