Revert "phy dp83867: Fix compilation with CONFIG_OF_MDIO=m"

This reverts commit 7f32541c.

This needs reverting too, as per requests.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/phy/dp83867.c

@@ -99,7 +99,7 @@ static int dp83867_config_intr(struct phy_device *phydev)
 	return phy_write(phydev, MII_DP83867_MICR, micr_status);
 }
 
-#if IS_ENABLED(CONFIG_OF_MDIO)
+#ifdef CONFIG_OF_MDIO
 static int dp83867_of_init(struct phy_device *phydev)
 {
 	struct dp83867_private *dp83867 = phydev->priv;