scsi: lpfc: Don't return internal MBXERR_ERROR code from probe function

Internal error codes happen to be positive, thus the PCI driver core
won't treat them as failure, but we do. This would cause a crash later
on as lpfc_pci_remove_one() is called (e.g. as shutdown function).

Fixes: 6d368e53 ("[SCSI] lpfc 8.3.24: Add resource extent support")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Acked-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>