scsi: virtio_scsi: Do not overwrite SCSI status

When a sense code is present we should not override the SAM status; the
driver already sets it based on the response from the hypervisor.

In addition we should only copy the sense buffer if one is actually
provided by the hypervisor.

Link: https://lore.kernel.org/r/20210622091153.29231-1-hare@suse.de


Fixes: 464a00c9 ("scsi: core: Kill DRIVER_SENSE")
Tested-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>