app/testpmd: add GENEVE parsing

app/testpmd: add GENEVE parsing

GENEVE is a widely used tunneling protocol in modern Virtualized
Networks. testpmd already supports parsing of several tunneling
protocols including VXLAN, VXLAN-GPE, GRE. This commit adds GENEVE
parsing of inner protocols (IPv4-0x0800, IPv6-0x86dd, Ethernet-0x6558)
based on IETF draft-ietf-nvo3-geneve-09. GENEVE is considered more
flexible than the other protocols.  In terms of protocol format GENEVE
header has a variable length options as opposed to other tunneling
protocols which have a fixed header size.

Signed-off-by: Ophir Munk <ophirmu@mellanox.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>