ravb: fix result value overwrite

The result value is overwritten by a return value of
ravb_ptp_interrupt().
Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com>
Acked-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/renesas/ravb_main.c

@@ -757,8 +757,8 @@ static irqreturn_t ravb_interrupt(int irq, void *dev_id)
 		result = IRQ_HANDLED;
 	}
 
-	if (iss & ISS_CGIS)
-		result = ravb_ptp_interrupt(ndev);
+	if ((iss & ISS_CGIS) && ravb_ptp_interrupt(ndev) == IRQ_HANDLED)
+		result = IRQ_HANDLED;
 
 	mmiowb();
 	spin_unlock(&priv->lock);