scsi: megaraid_sas: Target with invalid LUN ID is deleted during scan

The megaraid_sas driver supports single LUN for RAID devices. That is LUN
0. All other LUNs are unsupported. When a device scan on a logical target
with invalid LUN number is invoked through sysfs, that target ends up
getting removed.

Add LUN ID validation in the slave destroy function to avoid the target
deletion.

Link: https://lore.kernel.org/r/20220324094711.48833-1-chandrakanth.patil@broadcom.com
Signed-off-by: Chandrakanth patil <chandrakanth.patil@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>