net: phy: respect cached advertising when re-enabling EEE

If we remove modes from EEE advertisement and disable / re-enable EEE,
then advertisement is set to all supported modes. I don't think this is
what the user expects. So respect the cached advertisement and just fall
back to all supported modes if cached advertisement is empty.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://patch.msgid.link/c75f7f8b-5571-429f-abd3-ce682d178a4b@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: hkallweit

drivers/net/phy/phy-c45.c

@@ -1568,11 +1568,10 @@ int genphy_c45_ethtool_set_eee(struct phy_device *phydev,
 				phydev_warn(phydev, "At least some EEE link modes are not supported.\n");
 				return -EINVAL;
 			}
-		} else {
-			adv = phydev->supported_eee;
+			linkmode_copy(phydev->advertising_eee, adv);
+		} else if (linkmode_empty(phydev->advertising_eee)) {
+			phy_advertise_eee_all(phydev);
 		}
-
-		linkmode_copy(phydev->advertising_eee, adv);
 	}
 
 	phydev->eee_enabled = data->eee_enabled;