V4L/DVB (5135): Qt1010: correct hardlockup when an app access the DVB dongle

This patch changes qt1010.h to use dvb_usb_device struct instead of a
dvb_usb_adapter for accessing the private area of the driver.
Without this patch my PC hard locks when an application tries to access
the DVB tuner.

Signed-off-by: Jan Nijs <jan.nijs@scarlet.be>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>