net: stmmac: sunxi: remove of_get_phy_mode()

devm_stmmac_probe_config_dt() already gets the PHY mode from firmware,
which is stored in plat_dat->phy_interface. Therefore, we don't need to
get it in platform code.

Set gmac->interface from plat_dat->phy_interface.

Reviewed-by: Michal Kubiak <michal.kubiak@intel.com>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1tsIGx-005v0F-Ev@rmk-PC.armlinux.org.uk
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/stmicro/stmmac/dwmac-sunxi.c

@@ -116,11 +116,7 @@ static int sun7i_gmac_probe(struct platform_device *pdev)
 	if (!gmac)
 		return -ENOMEM;
 
-	ret = of_get_phy_mode(dev->of_node, &gmac->interface);
-	if (ret && ret != -ENODEV) {
-		dev_err(dev, "Can't get phy-mode\n");
-		return ret;
-	}
+	gmac->interface = plat_dat->phy_interface;
 
 	gmac->tx_clk = devm_clk_get(dev, "allwinner_gmac_tx");
 	if (IS_ERR(gmac->tx_clk)) {