lpfc: Fix to drop PLOGIs from fabric node till LOGO processing completes

The domain controller PLOGI's concurrent with prior LOGO's/unreg_rpi's
completing created a race condition where driver rpi ref count can
inadvertantly hit 0 and the rpi attempted to be freed. This error
sometimes resulted in Warning messages indicating kref.h via
lfpc_nlp_get+0x128.

Correct by dropping any new PLOGI until the prior nport state has settled.

Signed-off-by: Dick Kennedy <dick.kennedy@avagotech.com>
Signed-off-by: James Smart <james.smart@avagotech.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>

drivers/scsi/lpfc/lpfc_nportdisc.c

@@ -1874,7 +1874,7 @@ lpfc_rcv_logo_logo_issue(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp,
 	struct lpfc_iocbq *cmdiocb = (struct lpfc_iocbq *)arg;
 
 	spin_lock_irq(shost->host_lock);
-	ndlp->nlp_flag &= NLP_LOGO_ACC;
+	ndlp->nlp_flag |= NLP_LOGO_ACC;
 	spin_unlock_irq(shost->host_lock);
 	lpfc_els_rsp_acc(vport, ELS_CMD_ACC, cmdiocb, ndlp, NULL);
 	return ndlp->nlp_state;