scsi: hisi_sas: Remedy inconsistent PHY down state in software

Currently there are two scenarioes which may cause PHY state of hardware
(which is 0) is inconsistent with the state held in software:

- Unplug SAS wire before get_phys_state when SAS controller reset, then the
  interrupts of phy down are ignored, phy state is 0 before reset, and it
  also gets 0 after reset, so phy down doesn't occur even if unplugged SAS
  wire;

- For v3 hw later version, it will close bus when 2 bit ECC error occurs.
  So if unplug SAS wire at that time, interrupts of phy down also not
  occur. So at last it will cause host reset. It also get phy state 0
  before and after reset, the same issue occurs.

To solve it, use hisi_sas_phy_down() directly in rescan topology function.

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>