scsi: hisi_sas: Start delivery hisi_sas_task_exec() directly

scsi: hisi_sas: Start delivery hisi_sas_task_exec() directly

Currently we start delivery of commands to the DQ after returning from
hisi_sas_task_exec() with success.

Let's just start delivery directly in that function without having to check
if some local variable is set.

Link: https://lore.kernel.org/r/1639579061-179473-2-git-send-email-john.garry@huawei.com
Reviewed-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>