blk-integrity: use sysfs_emit

The correct way to emit data into sysfs is via sysfs_emit(), use it.

Also perform some trivial syntactic cleanups.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20230309-kobj_release-gendisk_integrity-v3-1-ceccb4493c46@weissschuh.net
Signed-off-by: Jens Axboe <axboe@kernel.dk>