net/mlx5e: Max mtu comparison fix

On change mtu the driver compares between hardware queried mtu and
software requested mtu. We need to compare between software
representation of the queried mtu and the requested mtu.

Fixes: facc9699f0 ('net/mlx5e: Fix HW MTU settings')
Signed-off-by: Doron Tsur <doront@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx5/core/en_main.c

@@ -1901,6 +1901,8 @@ static int mlx5e_change_mtu(struct net_device *netdev, int new_mtu)
 
 	mlx5_query_port_max_mtu(mdev, &max_mtu, 1);
 
+	max_mtu = MLX5E_HW2SW_MTU(max_mtu);
+
 	if (new_mtu > max_mtu) {
 		netdev_err(netdev,
 			   "%s: Bad MTU (%d) > (%d) Max\n",