scsi: target: Do not write NUL characters into ASCII configfs output

scsi: target: Do not write NUL characters into ASCII configfs output

[ Upstream commit c03b55f235e283cae49c88b9602fd11096b92eba ]

NUL characters are not allowed in ASCII configfs output. Hence this
patch.

Fixes: c66ac9db8d4a ("[SCSI] target: Add LIO target core v4.0.0-rc6")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251027184639.3501254-2-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>