The au0828 dev_state is actually a bit mask. It should not be
checking with "==" but, instead, with a logic and. There are some
places where it was doing it wrong.
Fix that by replacing the dev_state set/clear/test with the
bitops.
As reviewed by Shuah:
"Looks good. Tested running bind/unbind au0828 loop for 1000 times.
Didn't see any problems and the v4l2_querycap() problem has been
fixed with this patch.
After the above test, ran bind/unbind snd_usb_audio 1000 times.
Didn't see any problems. Generated media graph and the graph
looks good."