V4L/DVB (5954): Sync with DiBcom Driver Release 2.1.3 + some improvements

This changesets syncs the OpenSource driver for DiBcom demodulators
with version 2.1.3 of DiBcom reference driver. There were some
improvements since the last release for linux-dvb, e.g.:

- stepped AGC startup
- less space for initialization
- diversity synchronization

Furthermore this changeset contains the following things:

- latest AGC settings for MT2266-based devices (namely Nova-TD and other) will improve the sensitivity
- support for STK7700D reference design in dib0700-devices
- remove some line-breaks when debugging is enabled
- getting rid of layer between frontend_parameters and ofdm_channel used in dib*-drivers

Signed-off-by: Patrick Boettcher <pboettcher@dibcom.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>