net: phy: DP83TC811: Fix SGMII enable/disable

If SGMII was selected in the DT then the device should
write the SGMII enable bit.

If SGMII is not selected in the DT then the SGMII bit
should be disabled.
Signed-off-by: Dan Murphy <dmurphy@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/dp83tc811.c

@@ -284,20 +284,18 @@ static int dp83811_config_init(struct phy_device *phydev)
 	if (err < 0)
 		return err;
 
-	if (phydev->interface == PHY_INTERFACE_MODE_SGMII) {
 	value = phy_read(phydev, MII_DP83811_SGMII_CTRL);
-		if (!(value & DP83811_SGMII_EN)) {
+	if (phydev->interface == PHY_INTERFACE_MODE_SGMII) {
 		err = phy_write(phydev, MII_DP83811_SGMII_CTRL,
 					(DP83811_SGMII_EN | value));
-			if (err < 0)
-				return err;
 	} else {
 		err = phy_write(phydev, MII_DP83811_SGMII_CTRL,
 				(~DP83811_SGMII_EN & value));
+	}
+
 	if (err < 0)
+
 		return err;
-		}
-	}
 
 	value = DP83811_WOL_MAGIC_EN | DP83811_WOL_SECURE_ON | DP83811_WOL_EN;