[media] cxusb: Add support for TechnoTrend TT-connect CT2-4650 CI

TechnoTrend TT-connect CT2-4650 CI (0b48:3012) is an USB DVB-T2/C tuner with
the following components:

 USB interface: Cypress CY7C68013A-56LTXC
 Demodulator: Silicon Labs Si2168-A20
 Tuner: Silicon Labs Si2158-A20
 CI chip: CIMaX SP2HF

The firmware for the tuner is the same as for TechnoTrend TT-TVStick CT2-4400.
See https://www.mail-archive.com/linux-media@vger.kernel.org/msg76944.html

The demodulator needs a firmware that can be extracted from the Windows drivers.
File ttConnect4650_64.sys should be extracted from
http://www.tt-downloads.de/bda-treiber_4.1.0.4.zip

 (MD5 sum below).

3464bfc37a47b4032568718bacba23fb  ttConnect4650_64.sys

Then the firmware can be extracted:
dd if=ttConnect4650_64.sys ibs=1 skip=273376 count=6424 of=dvb-demod-si2168-a20-01.fw

The SP2 CI module requires a definition of a function cxusb_tt_ct2_4650_ci_ctrl
that is passed on to the SP2 driver and called back for CAM operations.

[crope@iki.fi: meld USB ID define patch to this]
Signed-off-by: Olli Salonen <olli.salonen@iki.fi>
Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Antti Palosaari <crope@iki.fi>

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>