[PATCH] net: ethernet: mtk_eth_soc: fix mtu warning

[Frank Wunderlich]

From: René van Dorst <opensource at vdorst.com>

in recent Kernel-Versions there are warnings about incorrect MTU-Size
like these:

mt7530 mdio-bus:00: nonfatal error -95 setting MTU on port x
eth0: mtu greater than device maximum
mtk_soc_eth 1b100000.ethernet eth0: error -22 setting MTU to include DSA overhead

Signed-off-by: René van Dorst <opensource at vdorst.com>
Signed-off-by: Frank Wunderlich <frank-w at public-files.de>

Fixes: bfcb813203 ("net: dsa: configure the MTU for switch ports")
Fixes: 72579e14a1 ("net: dsa: don't fail to probe if we couldn't set the MTU")
Fixes: 7a4c53bee3 ("net: report invalid mtu value via netlink extack")
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 85735d32ecb0..00e3d70f7d07 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -2891,6 +2891,10 @@ static int mtk_add_mac(struct mtk_eth *eth, struct device_node *np)
 	eth->netdev[id]->irq = eth->irq[0];
 	eth->netdev[id]->dev.of_node = np;

+	eth->netdev[id]->mtu = 1536;
+	eth->netdev[id]->min_mtu = ETH_MIN_MTU;
+	eth->netdev[id]->max_mtu = 1536;
+
 	return 0;

 free_netdev:
--
2.25.1