scsi: libsas: add lun number check in .slave_alloc callback

hulk inclusion
category: bugfix
bugzilla: 51878
CVE: NA

-------------------------------------------------

We found that offline a sata device on hisi sas control and then
scanning the host can probe 255 non-existent devices into system.

[root@localhost ~]# lsscsi
  [2:0:0:0]    disk    ATA      Samsung SSD 860  2B6Q  /dev/sda
  [2:0:1:0]    disk    ATA      WDC WD2003FYYS-3 1D01  /dev/sdb
  [2:0:2:0]    disk    SEAGATE  ST600MM0006      B001  /dev/sdc

 1) echo "offline" > /sys/block/sdb/device/state
 2) echo "- - -" > /sys/class/scsi_host/host2/scan

Then, we can see another 255 non-existent devices in system:
  [root@localhost ~]# lsscsi
  [2:0:0:0]    disk    ATA      Samsung SSD 860  2B6Q  /dev/sda
  [2:0:1:0]    disk    ATA      WDC WD2003FYYS-3 1D01  /dev/sdb
  [2:0:1:1]    disk    ATA      WDC WD2003FYYS-3 1D01  /dev/sdh
  ...
  [2:0:1:255]  disk    ATA      WDC WD2003FYYS-3 1D01  /dev/sdjb

After REPORT LUN command issued to the offline device fail, it tries
to do a sequential scan and probe all devices whose lun is not 0
successfully.

To fix the problem, we try to do same things as commit 2fc62e2a
("[SCSI] libsas: disable scanning lun > 0 on ata devices"), which
will prevent the device whose lun number is not zero probe into system.

Reported-by: Wu Bo <wubo40@huawei.com>
Suggested-by: John Garry <john.garry@huawei.com>
Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Reviewed-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>