net/mlx5: Geneve, Add basic Geneve encap/decap flow table capabilities

Introduce support for Geneve flow specification and allow
the creation of rules that are matching on basic Geneve
protocol fields: VNI, OAM bit, protocol type, options length.

Reviewed-by: Oz Shlomo <ozsh@mellanox.com>
Signed-off-by: Yevgeny Kliteynik <kliteyn@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>