media: ngene: add support for DuoFlex S2 V4 addon modules

Add support for the STV0910/STV6111/LNBH25 based DuoFlex S2 V4 DVB-S2
addon modules by recognizing them from their XO2 type value and using
the auxiliary stv0910, stv6111 and lnbh25 driver to form a complete
DVB frontend.

This also adds autoselection (if MEDIA_SUBDRV_AUTOSELECT) of the STV0910,
STV6111 and LNBH25 demod/tuner/LNB-IC drivers to Kconfig.

Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>