[linux-dvb] only one read access to cx88-devices possible

[Fabian Förg]

Hello,

I realized that only one read access is possible to devices that use the 
cx88 driver.
In my case it is a Hauppauge WinTV Nova-S-Plus DVB-S card.
You can reproduce it with the following test:
Launch femon concurrently two or more times. Only one femon is able to 
read from the card.
Oliver Endriss confirmed that bug after looking in cx88-dvb.c.
Usually, only one write access but an arbitrary amount of read accesses 
should be allowed.

Greets,
Fabian