scsi: MAINTAINERS: Add the linux-scsi mailing list to the ISCSI entry

Most people who review iSCSI are following linux-scsi, but some are not in
open-scsi. Make sure we are routing iSCSI patches to the right list.

Link: https://lore.kernel.org/r/85h82rvqza.fsf@collabora.com


Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>