Return ERR even if there are pending data, but hw is not running.  Do not
decrement count in poll, do it in ioctl, where data are actually read.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>