block: remove a superflous queue kobject reference

kobject_add already adds a reference to the parent that is dropped
on deletion, so don't bother grabbing another one.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220628171850.1313069-3-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>