[media] cx23855: add support for DVBSky T980C (no CI support)

This patch adds basic support for DVBSky T980C card. CI interface is not supported.

DVBSky T980C is a PCIe card with the following components:
- CX23885 PCIe bridge
- Si2168-A20 demodulator
- Si2158-A20 tuner
- CIMaX SP2 CI chip

The demodulator and tuner need firmware. They're the same as used with TT CT2-4650 CI:
https://www.mail-archive.com/linux-media@vger.kernel.org/msg78033.html



Signed-off-by: Olli Salonen <olli.salonen@iki.fi>
Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>