atl1c: adjust max mtu according to Mikrotik 10/25G NIC ability

The new Mikrotik 10/25G NIC supports jumbo frames. Jumbo frames are
supported for TSO as well.

This enables the support for mtu up to 9500 bytes.
Signed-off-by: Gatis Peisenieks <gatis@mikrotik.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/atheros/atl1c/atl1c_main.c

@@ -478,6 +478,9 @@ static void atl1c_set_rxbufsize(struct atl1c_adapter *adapter,
 static netdev_features_t atl1c_fix_features(struct net_device *netdev,
 	netdev_features_t features)
 {
+	struct atl1c_adapter *adapter = netdev_priv(netdev);
+	struct atl1c_hw *hw = &adapter->hw;
+
 	/*
 	 * Since there is no support for separate rx/tx vlan accel
 	 * enable/disable make sure tx flag is always in same state as rx.
@@ -487,8 +490,10 @@ static netdev_features_t atl1c_fix_features(struct net_device *netdev,
 	else
 		features &= ~NETIF_F_HW_VLAN_CTAG_TX;
 
+	if (hw->nic_type != athr_mt) {
 		if (netdev->mtu > MAX_TSO_FRAME_SIZE)
 			features &= ~(NETIF_F_TSO | NETIF_F_TSO6);
+	}
 
 	return features;
 }
@@ -517,6 +522,9 @@ static void atl1c_set_max_mtu(struct net_device *netdev)
 		netdev->max_mtu = MAX_JUMBO_FRAME_SIZE -
 			(ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN);
 		break;
+	case athr_mt:
+		netdev->max_mtu = 9500;
+		break;
 		/* The 10/100 devices don't support jumbo packets, max_mtu 1500 */
 	default:
 		netdev->max_mtu = ETH_DATA_LEN;