net: fec: only enable mdio interrupt before phy device link up

Before phy device link up, we only enable FEC mdio interrupt, which
is more reasonable.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/fec_main.c

@@ -1075,7 +1075,10 @@ fec_restart(struct net_device *ndev)
 		fec_ptp_start_cyclecounter(ndev);
 
 	/* Enable interrupts we wish to service */
-	writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);
+	if (fep->link)
+		writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);
+	else
+		writel(FEC_ENET_MII, fep->hwp + FEC_IMASK);
 
 	/* Init the interrupt coalescing */
 	fec_enet_itr_coal_init(ndev);