Revert "net/mlx5e: Block offload of outer header csum for GRE tunnel"

This reverts commit 54e1217b.

Although the NIC doesn't support offload of outer header CSUM, using
gso_partial_features allows offloading the tunnel's segmentation. The
driver relies on the stack CSUM calculation of the outer header. For
this, NETIF_F_GSO_GRE_CSUM must be a member of the device's features.

Fixes: 54e1217b ("net/mlx5e: Block offload of outer header csum for GRE tunnel")
Signed-off-by: NAya Levin <ayal@nvidia.com>
Reviewed-by: NGal Pressman <gal@nvidia.com>
Signed-off-by: NSaeed Mahameed <saeedm@nvidia.com>

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

@@ -4799,9 +4799,12 @@ static void mlx5e_build_nic_netdev(struct net_device *netdev)
 	}
 
 	if (mlx5e_tunnel_proto_supported_tx(mdev, IPPROTO_GRE)) {
-		netdev->hw_features     |= NETIF_F_GSO_GRE;
-		netdev->hw_enc_features |= NETIF_F_GSO_GRE;
-		netdev->gso_partial_features |= NETIF_F_GSO_GRE;
+		netdev->hw_features     |= NETIF_F_GSO_GRE |
+					   NETIF_F_GSO_GRE_CSUM;
+		netdev->hw_enc_features |= NETIF_F_GSO_GRE |
+					   NETIF_F_GSO_GRE_CSUM;
+		netdev->gso_partial_features |= NETIF_F_GSO_GRE |
+						NETIF_F_GSO_GRE_CSUM;
 	}
 
 	if (mlx5e_tunnel_proto_supported_tx(mdev, IPPROTO_IPIP)) {