V4L/DVB (3572): Cxusb: conditionalize gpio write for the medion box

This patch removes the (harmless) -ETIMEDOUT during device init
for the DViCO FusionHDTV Bluebird boxes, by conditionalizing the
gpio write inside cxusb_i2c_xfer to happen only for Medion boxes.

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>