usb/misc/chaoskey: Cleanup probe failure paths

Shares the cleanup code between all probe failure paths, instead of
having per-failure cleanup at each point in the function.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>