scsi: cxlflash: Setup AFU PASID

Per the OCXL specification, the maximum PASID supported by the AFU is
indicated by a field within the configuration space. Similar to acTags,
implementations can choose to use any sub-range of PASID within their assigned
range. For cxlflash, the entire range is used.

Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Reviewed-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>