scsi: acornscsi: Remove tagged queuing vestiges

The acornscsi driver has a config option to enable tagged queuing, but this
option gets disabled in the driver itself with the comment 'needs to be
debugged'.  As this is a _really_ old driver I doubt anyone will be wanting
to invest time here, so remove the tagged queue vestiges and make our lives
easier.

[jpg: Use scsi_cmd_to_rq()]

Link: https://lore.kernel.org/r/1631696835-136198-3-git-send-email-john.garry@huawei.com
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>