scsi: cxlflash: MMIO map the AFU

When the AFU is configured, the global and per process MMIO regions are
presented by the configuration space. Save these regions and map the global
MMIO region that is used to access all of the control and provisioning data in
the AFU.

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