net: mediatek: handle alternative name for pn_swap property

Handle alternative name for pn_swap property as upstream linux use
mediatek,pnswap.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
diff --git a/drivers/net/mtk_eth.c b/drivers/net/mtk_eth.c
index 94f17a9..5098afe 100644
--- a/drivers/net/mtk_eth.c
+++ b/drivers/net/mtk_eth.c
@@ -1964,7 +1964,9 @@
 			return -ENODEV;
 		}
 
-		priv->pn_swap = ofnode_read_bool(args.node, "pn_swap");
+		/* Upstream linux use mediatek,pnswap instead of pn_swap */
+		priv->pn_swap = ofnode_read_bool(args.node, "pn_swap") ||
+				ofnode_read_bool(args.node, "mediatek,pnswap");
 	} else if (priv->phy_interface == PHY_INTERFACE_MODE_USXGMII) {
 		/* get corresponding usxgmii phandle */
 		ret = dev_read_phandle_with_args(dev, "mediatek,usxgmiisys",