net: hns3: remove add/del_tunnel_udp in hns3_enet module

The add/del_tunnel_udp is not implemented in hclge_main moulde,
the NETIF_F_RX_UDP_TUNNEL_PORT feature bit is added automatically
by stack when ndo_udp_tunnel_add is not null in dev->netdev_ops.

This patch removes the add/del_tunnel_udp related function, for
we do not support this feature now.

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>