If the same ttyIx device was opened by two processes the module was not
released and so the usage count went never to zero again.  This oneliner fixes
the issue.

Signed-off-by: Oskar Senft <o.senft@sirrix.com>
Signed-off-by: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>