scsi: hisi_sas: add controller reset

There are some scenarios that we need to warm-reset to reset registers
of SAS controller. During reset we disable interrupts/DQs/PHYs, and
after reset we re-init the hardware and rescan the topology to see if
anything changed.

Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>