scsi: cxlflash: Abstract hardware dependent assignments

As a staging cleanup to support transport specific builds of the cxlflash
module, relocate device dependent assignments to header files. This will
avoid littering the core driver with conditional compilation logic.

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>