Add new module param "allow_restart" to control scsi_device's allow_restart
flag. This flag determines if EH is triggered after a command completes
with sense_key 0x6, ASC 0x4 and ASCQ 0x2. EH would be triggered if
allow_restart=1 in this condition.

The new param can be used with the error injection capability to test how
commands completing with sense_key 0x6, ASC 0x4 and ASCQ 0x2 are handled.
Signed-off-by: Wenchao Hao <haowenchao2@huawei.com>
Link: https://lore.kernel.org/r/20231010092051.608007-11-haowenchao2@huawei.comTested-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>