net/mlx5e: Avoid creating tunnel headers for local route

It could be local and remote are on the same machine and the route
result will be a local route which will result in creating encap id
with src/dst mac address of 0.

Fixes: a54e20b4 ("net/mlx5e: Add basic TC tunnel set action for SRIOV offloads")
Signed-off-by: Roi Dayan <roid@nvidia.com>
Reviewed-by: Maor Dickman <maord@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c

@@ -124,6 +124,11 @@ static int mlx5e_route_lookup_ipv4_get(struct mlx5e_priv *priv,
 	if (IS_ERR(rt))
 		return PTR_ERR(rt);
 
+	if (rt->rt_type != RTN_UNICAST) {
+		ret = -ENETUNREACH;
+		goto err_rt_release;
+	}
+
 	if (mlx5_lag_is_multipath(mdev) && rt->rt_gw_family != AF_INET) {
 		ret = -ENETUNREACH;
 		goto err_rt_release;