This patch adds L2TPv2 control message and 5 types of data message
support for testpmd.
The added L2TPv2 message types are listed below:
1. L2TPv2 control
2. L2TPv2
3. L2TPv2 + length option
4. L2TPv2 + sequence option
5. L2TPv2 + offset option
6. L2TPv2 + length option + sequence option
Signed-off-by: Jie Wang <jie1x.wang@intel.com>
Acked-by: Ori Kam <orika@nvidia.com>