vhost scsi: fix lun reset completion handling

vhost scsi owns the scsi se_cmd but lio frees the se_cmd->se_tmr
before calling release_cmd, so while with normal cmd completion we
can access the se_cmd from the vhost work, we can't do the same with
se_cmd->se_tmr. This has us copy the tmf response in
vhost_scsi_queue_tm_rsp to our internal vhost-scsi tmf struct for
when it gets sent to the guest from our worker thread.

Fixes: efd838fe ("vhost scsi: Add support for LUN resets.")
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Link: https://lore.kernel.org/r/1605887459-3864-1-git-send-email-michael.christie@oracle.com


Signed-off-by: Michael S. Tsirkin <mst@redhat.com>