[media] si2165: Add demod driver for DVB-T only

DVB-T was tested  with 8MHz BW channels in germany
This driver is the simplest possible, it uses automatic mode for all
parameters (TPS).

Added spectrum inversion support.

Signed-off-by: Matthias Schwarzott <zzam@gentoo.org>
Tested-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>