scsi: hisi_sas: modify hisi_sas_abort_task() for SSP

Currently an internal abort is executed regardless of the result of the
TMF. We should also check the result of the internal abort to see if we
should free the slot.

So change the status code STAT_IO_COMPLETE to TMF_RESP_FUNC_SUCC,
meaning the slot has been successfully aborted.

Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>