scsi: hisi_sas: Add debugfs file structure for CQ

Create a file structure which was used to save the memory address and CQ
pointer for CQ at debugfs. This structure is bound to the corresponding
debugfs file, it can help callback function of debugfs file to get what it
need.

Link: https://lore.kernel.org/r/1571926105-74636-7-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>