Add patch to support mp2p ipip tunnel

[lolyu]

Add vpp patch to support mp2p ipip tunnel. This is to provide the same behavior as SAI P2MP ipinip tunnel.

VPP PR: https://gerrit.fd.io/r/c/vpp/+/45685

with this patch, ipip tunnel on vpp sonic t0:

vpp# show ipip tunnel
[0] instance 0 mp2p src 10.0.0.56 table-ID 0 sw-if-idx 76 flags [decap-copy-ecn ] dscp CS0
[1] instance 1 mp2p src 10.0.0.58 table-ID 0 sw-if-idx 77 flags [decap-copy-ecn ] dscp CS0
[2] instance 2 mp2p src 10.0.0.60 table-ID 0 sw-if-idx 78 flags [decap-copy-ecn ] dscp CS0
[3] instance 3 mp2p src 10.0.0.62 table-ID 0 sw-if-idx 79 flags [decap-copy-ecn ] dscp CS0
[4] instance 4 mp2p src 10.1.0.32 table-ID 0 sw-if-idx 80 flags [decap-copy-ecn ] dscp CS0
[5] instance 5 mp2p src 192.168.0.1 table-ID 0 sw-if-idx 81 flags [decap-copy-ecn ] dscp CS0
[6] instance 6 mp2p src fc00:1::32 table-ID 0 sw-if-idx 82 flags [decap-copy-ecn ] dscp CS0
[7] instance 7 mp2p src fc00::71 table-ID 0 sw-if-idx 83 flags [decap-copy-ecn ] dscp CS0
[8] instance 8 mp2p src fc00::75 table-ID 0 sw-if-idx 84 flags [decap-copy-ecn ] dscp CS0
[9] instance 9 mp2p src fc00::79 table-ID 0 sw-if-idx 85 flags [decap-copy-ecn ] dscp CS0
[10] instance 10 mp2p src fc00::7d table-ID 0 sw-if-idx 86 flags [decap-copy-ecn ] dscp CS0
[11] instance 11 mp2p src fc02:1000::1 table-ID 0 sw-if-idx 87 flags [decap-copy-ecn ] dscp CS0

Signed-off-by: Longxiang Lyu lolv@microsoft.com

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[yue-fred-gao]

lgtm

[yxieca]

Can we upstream this to vpp?

[lolyu]

Can we upstream this to vpp?

Hi @yxieca, vpp pr link: https://gerrit.fd.io/r/c/vpp/+/45685