The core md code calls the ->free method which already frees conf.

Fixes: 0c031fd3 ("md: Move alloc/free acct bioset in to personality")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20240613084839.1044015-3-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>