hisi_sas: Add cq structure initialization

Each completion queue has a structure. This is mainly for passing to irq
handler so we know which queue the irq occured on.

Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>