V4L/DVB (7227): saa7134: fixed DVB-S support for Medion/Creatix CTX948

The I2C bus interface of the LNB supply sits behind the i2c gate of the
tda10086, so wrappers were necessary for the set_voltage functions.

For the time being, the board will show up as MD8800

Many thanks to Hermann Pitton for his help

Signed-off-by: Hartmut Hackmann <hartmut.hackmann@t-online.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>