scsi: hisi_sas: relocate get_ncq_tag_v2_hw()

Relocate get_ncq_tag_v2_hw() to a common location, as future hw versions
will require it.  Also rename with "hisi_sas_" prefix for consistency.

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>