net: phy: genphy_c45_pma_baset1_setup_master_slave: do no set unknown configuration

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

@@ -86,9 +86,10 @@ int genphy_c45_pma_baset1_setup_master_slave(struct phy_device *phydev)
 		break;
 	case MASTER_SLAVE_CFG_SLAVE_FORCE:
 	case MASTER_SLAVE_CFG_SLAVE_PREFERRED:
+		break;
 	case MASTER_SLAVE_CFG_UNKNOWN:
 	case MASTER_SLAVE_CFG_UNSUPPORTED:
-		break;
+		return 0;
 	default:
 		phydev_warn(phydev, "Unsupported Master/Slave mode\n");
 		return -EOPNOTSUPP;