scsi: hisi_sas: Use autosuspend for the host controller

scsi: hisi_sas: Use autosuspend for the host controller

The controller may frequently enter and exit suspend for each I/O which we
need to deal with. This is inefficient and may cause too much suspend and
resume activity for the controller.  To avoid this, use a default 5s
autosuspend for the controller to stop frequently suspending and
resuming. This value may still be modified via sysfs interfaces.

Link: https://lore.kernel.org/r/1639999298-244569-16-git-send-email-chenxiang66@hisilicon.com
Acked-by: John Garry <john.garry@huawei.com>
Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>