linux: Add support for TechnoTrend CT2-4400 and 4650 USB tuners

Here's a PR against the master.

Kernel 3.17 supports TechnoTrend CT2-4400v1.

This patch adds support for:
TechnoTrend CT2-4400v2
TechnoTrend CT2-4650 CI (including the CI slot support)

It looks a bit large, but most of it comes from adding the driver for CIMaX SP2 CI controller driver. Furthermore I took the recent changes made to Si2168 demodulator and Si2157 tuner as there are a few good improvements there (PLP ID support for DVB-T2, improved firmware handling, support for different TS modes).

Tested working with x86_64 architecture (with CT2-4650 and CT2-4400v2).