net: fec: use mac-managed PHY PM

Use the new mac_managed_pm flag to work around an issue with KSZ8081 PHY
that becomes unstable when a soft reset is triggered during aneg.

Reported-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Tested-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/freescale/fec_main.c

@@ -2048,6 +2048,8 @@ static int fec_enet_mii_probe(struct net_device *ndev)
 	fep->link = 0;
 	fep->full_duplex = 0;
 
+	phy_dev->mac_managed_pm = 1;
+
 	phy_attached_info(phy_dev);
 
 	return 0;
@@ -3864,6 +3866,7 @@ static int __maybe_unused fec_resume(struct device *dev)
 		netif_device_attach(ndev);
 		netif_tx_unlock_bh(ndev);
 		napi_enable(&fep->napi);
+		phy_init_hw(ndev->phydev);
 		phy_start(ndev->phydev);
 	}
 	rtnl_unlock();