scsi: hisi_sas: update some v3 register init settings

This patch updates some register setting according to recommendation
from HW designer and experiment.

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>