The v2 SAS controller needs more time to detect channel idle
and send setup link request than SATA disk does, so it is
difficult for the SAS controller to setup an STP link. Therefore
it may cause some IO timeouts.

We need to periodically configure the SAS controller so it
doesn't receive STP setup requests from SATA disks for a while,
so IO can be sent during this period.
Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>