This fixes the issue of failing to hot plugin more than 7 disks.
SRB flag is set to 0x20 if the specified LUN is invalid by Hyper-v host, and
the INQUIRY response will not be set by Hyper-v host. That is why INQUIRY
on invalid lun get all zero values. In addition, TUR (Test Unit Ready) command
on invalid LUN also makes SRB flag be 0x20.
VM shall response to CAM layer with CAM_SEL_TIMEOUT to filter those
invalid LUNs. Never use CAM_DEV_NOT_THERE which will block LUN scan
for LUN number higher than 7.
Submitted by: Hongjiang Zhang <honzhan microsoft com>