scsi: target: iscsi: Stop using sprintf() in iscsi_target_configfs.c

Get rid of sprintf() in favor of sysfs_emit(). The latter ensures not to
overflow the given buffer.

Signed-off-by: Konstantin Shelekhin <k.shelekhin@yadro.com>
Link: https://lore.kernel.org/r/20230722152657.168859-3-k.shelekhin@yadro.com


Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>