media: ddbridge: support for CineS2 V7(A) and DuoFlex S2 V4 hardware

This adds all required glue code to support - in conjunction with the new
stv0910 and stv6111 demod/tuner drivers and additionally the lnbh25 LNB
controller driver - all current DVB-S/S2 hardware (bridges and flex
modules) from Digital Devices like the DD CineS2 V7 and V7A, current
S2 V4 DuoFlex modules, and probably all upcoming devices based on this
STV0910/STV6111/LNBH25 hardware stack.

Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Tested-by: Richard Scobie <r.scobie@clear.net.nz>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>