app/testpmd: support GENEVE option item

app/testpmd: support GENEVE option item

The patch adds the GENEVE option rte flow item support to
command line interpreter. The flow command with GENEVE
option items looks like:

  flow create 0 ingress pattern eth / ipv4 / udp / geneve vni is 100 /
       geneve-opt class is 99 length is 1 type is 0 data is 0x669988 /
       end actions drop / end

The option length should be specified in 32-bit words, this
value specifies the length of the data pattern/mask arrays (should be
multiplied by sizeof(uint32_t) to be expressed in bytes. If match
on the length itself is not needed the mask should be set to zero, in
this case length is used to specify the pattern/mask array lengths only.

Signed-off-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
Acked-by: Ori Kam <orika@nvidia.com>