V4L/DVB (4465): Attach the dib3000mc correctly

Flynn Marquardt found out that there is problem with the new dib3000mc-driver
when using with the real dib3000mc. It resulted in a segfault.
Fixed two things: use the correct I2C address and do not attach a tuner, when
the demod was previously failing.

Signed-off-by: Patrick Boettcher <pb@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>