scsi: cxlflash: SISlite updates to support 4 ports

Update the SISlite header to support 4 ports as outlined in the SISlite
specification. Address fallout from structure renames and refreshed
organization throughout the driver. Determine the number of ports supported by
a card from the global port selection mask register reset value.

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