scsi: hisi_sas: Set the BIST init value before enabling BIST

commit 65a3b8bd56942dc988b8c05615bd3f510a10012b upstream.

If set the BIST init value after enabling BIST, there may be still some few
error bits. According to the process, need to set the BIST init value
before enabling BIST.

Fixes: 97b151e7 ("scsi: hisi_sas: Add BIST support for phy loopback")
Link: https://lore.kernel.org/r/1571926105-74636-3-git-send-email-john.garry@huawei.com


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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>