scsi: hisi_sas: Move debugfs code to v3 hw driver

Relocate all the debugfs code for DFX to v3 hw since no other versions
support it.

Link: https://lore.kernel.org/r/1606207594-196362-4-git-send-email-john.garry@huawei.com


Signed-off-by: Luo Jiaxing <luojiaxing@huawei.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>