scsi: bnx2fc: Adjust bnx2fc_npiv_create_vports for WWNNs from NVRAM that are zero.

Some vports addresses stored in NVRAM may have zero for the WWNN.  Adjust
the WWNN that we'll use to be the same as the WWPN.

Signed-off-by: Chad Dupuis <chad.dupuis@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>