scsi: cxlflash: Allow cards without WWPN VPD to configure

Currently, all adapters that cxlflash supports must have WWPN VPD
keywords to complete configuration. This was required as cards with
external FC ports needed to be programmed with WWPNs.

Newer supported cards do not have an external FC interface and therefore
do not require WWPN. To support backwards compatibility, these devices
have included 'dummy' WWPN VPD with WWPN values of zero. This however
places a dependency that all future cards have WWPN VPD, which may not
always be the case.

Allow for cards to not have WWPN, designating which cards are expected
to have it in order to configure properly.

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>