netcat: allow multiple readers to work properly

Now multiple "users" can open the device node and have the music
streamed to them as needed.  No "only one reader allowed" restriction
anymore.  Bonus is that the local static variables are now gone.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Merge pull request #13 from gregkh/multiuser

netcat: allow multiple readers to work properly