With (some) Technisat cards you cannot run multiple DVB applications
in parallel and switch the channel at the same time.
There seems to be a problem on the interfaces or even inside the flexcop-device
that can't handle interruption on the streaming interface.
This patch adds a watchdog to check whether data is supposed to come in
(streaming PIDs are requested) and if no data is seen within 400ms (default) it
resets the streaming/pid-filtering hardware.
This patch is urgently needed to support the rev 2.8 of the hardware and solves
problem occassionally seen on older hardware.