scsi: hisi_sas: Fix setting of hisi_sas_slot.is_internal

The hisi_sas_slot.is_internal member is not set properly for ATA commands
which the driver sends directly. A TMF struct pointer is normally used as a
test to set this, but it is NULL for those commands. It's not ideal, but
pass an empty TMF struct to set that member properly.

Link: https://lore.kernel.org/r/1643627607-138785-1-git-send-email-john.garry@huawei.com
Fixes: dc313f6b

 ("scsi: hisi_sas: Factor out task prep and delivery code")
Reported-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>