kernel: allow device-tree configuration of at803x

This commit adds the ability to configure specific functions of the
at803x series ethernet-PHYs, which were previously configured
exclusively with the help of platform-data, via device-tree.

This is needed to fully support existing boards of the ar71xx platform.

Signed-off-by: David Bauer <mail@david-bauer.net>

target/linux/generic/pending-4.14/736-net-phy-at803x-allow-to-configure-via-dt.patch

@@ -0,0 +1,49 @@
+Index: linux-4.14.60/drivers/net/phy/at803x.c
+===================================================================
+--- linux-4.14.60.orig/drivers/net/phy/at803x.c
++++ linux-4.14.60/drivers/net/phy/at803x.c
+@@ -354,6 +354,14 @@ static int at803x_config_init(struct phy
+ 				AT803X_DEBUG_TX_CLK_DLY_EN, 0);
+ 	}
+ 
++#ifdef CONFIG_OF_MDIO
++	if (phydev->mdio.dev.of_node &&
++		of_property_read_bool(phydev->mdio.dev.of_node,
++				      "at803x-disable-smarteee")) {
++		at803x_disable_smarteee(phydev);
++	}
++#endif
++
+ 	return 0;
+ }
+ 
+@@ -392,6 +400,7 @@ static void at803x_link_change_notify(st
+ {
+ 	struct at803x_priv *priv = phydev->priv;
+ 	struct at803x_platform_data *pdata;
++	u8 fixup_rgmii_tx_delay = 0;
+ 	pdata = dev_get_platdata(&phydev->mdio.dev);
+ 
+ 	/*
+@@ -421,8 +430,19 @@ static void at803x_link_change_notify(st
+ 	} else {
+ 		priv->phy_reset = false;
+ 	}
+-	if (pdata && pdata->fixup_rgmii_tx_delay &&
+-	    phydev->speed != priv->prev_speed) {
++
++	if (pdata && pdata->fixup_rgmii_tx_delay)
++		fixup_rgmii_tx_delay = 1;
++
++#ifdef CONFIG_OF_MDIO
++	if (phydev->mdio.dev.of_node &&
++		of_property_read_bool(phydev->mdio.dev.of_node,
++				      "at803x-fixup-rgmii-tx-delay")) {
++			fixup_rgmii_tx_delay = 1;
++	}
++#endif
++
++	if (fixup_rgmii_tx_delay && phydev->speed != priv->prev_speed) {
+ 		switch (phydev->speed) {
+ 		case SPEED_10:
+ 		case SPEED_100: