scsi: cxlflash: Support reading adapter VPD data

Use the PCI VPD services to support reading the VPD data of the underlying
adapter.

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