lpfc: Fix DMA faults observed upon plugging loopback connector

Driver didn't program the REG_VFI mailbox correctly, giving the adapter
bad addresses.

Signed-off-by: Dick Kennedy <dick.kennedy@avagotech.com>
Signed-off-by: James Smart <james.smart@avagotech.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>