net: phy: genphy_c45_baset1_an_config_aneg: do no set unknown configuration

Do not change default master/slave autoneg configuration if no
changes was requested.

Fixes: 3da8ffd8 ("net: phy: Add 10BASE-T1L support in phy-c45")
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/phy-c45.c

@@ -191,8 +191,12 @@ static int genphy_c45_baset1_an_config_aneg(struct phy_device *phydev)
 	case MASTER_SLAVE_CFG_MASTER_PREFERRED:
 	case MASTER_SLAVE_CFG_SLAVE_PREFERRED:
 		break;
+	case MASTER_SLAVE_CFG_UNKNOWN:
+	case MASTER_SLAVE_CFG_UNSUPPORTED:
+		return 0;
 	default:
-		break;
+		phydev_warn(phydev, "Unsupported Master/Slave mode\n");
+		return -EOPNOTSUPP;
 	}
 
 	switch (phydev->master_slave_set) {