I would rather not change the values which are provided from the driver. I
would rather take the original values and try to use them in a sane way.
I have not seen other places where driver shost config values are modified
by the core code.
Wrt. .cmd_per_lun, I think it is safe to modify it into one correct
depth because almost all drivers are just producer of .cmd_per_lun. And
except for debug purpose, there are only three consumers of .cmd_per_lun
in scsi, and all are for scsi_change_queue_depth():