scsi: target: Add atomic se_device fields

scsi: target: Add atomic se_device fields

Add atomic fields to the se_device and export them in configfs.

Initially only target_core_iblock will be supported and we will inherit
all the settings from the block layer.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
jpg: Stop being allowed to configure atomic write alignment,
Signed-off-by: John Garry <john.g.garry@oracle.com>
Link: https://patch.msgid.link/20251020103820.2917593-3-john.g.garry@oracle.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>