net: phy: report link partner features through ethtool

The PHY library already reads the MII_STAT1000 and MII_LPA registers in
genphy_read_status(), so extend it to also populate the PHY device link
partner advertised features such that we can feed this back into ethtool
when asked for it in phy_ethtool_gset().

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index d6447b3..6db3659 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -839,6 +839,8 @@
 	if (err)
 		return err;
 
+	phydev->lp_advertising = 0;
+
 	if (AUTONEG_ENABLE == phydev->autoneg) {
 		if (phydev->supported & (SUPPORTED_1000baseT_Half
 					| SUPPORTED_1000baseT_Full)) {
@@ -852,6 +854,8 @@
 			if (adv < 0)
 				return adv;
 
+			phydev->lp_advertising =
+				mii_stat1000_to_ethtool_lpa_t(lpagb);
 			lpagb &= adv << 2;
 		}
 
@@ -860,6 +864,8 @@
 		if (lpa < 0)
 			return lpa;
 
+		phydev->lp_advertising |= mii_lpa_to_ethtool_lpa_t(lpa);
+
 		adv = phy_read(phydev, MII_ADVERTISE);
 
 		if (adv < 0)