scsi: hisi_sas: avoid potential v2 hw interrupt issue

When some interrupts happen together, we need to process every interrupt
one-by-one, and should not return immediately when one interrupt process
is finished being processed.

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>