pktcdvd: add kobject_put when kobject register fails

In kobject_register, the kobject reference is get in kobject_init, and then
kobject_add.  If kobject_add fail, it will only cleanup the reference got
by itself.

Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Greg KH <greg@kroah.com>
Cc: Peter Osterlund <petero2@telia.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>