scsi: hisi_sas: fix internal abort slot timeout bug

When an internal abort times out in hisi_sas_internal_task_abort(),
goto the exit label in and not go through the other task status
checks.

Signed-off-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>