IB/mlx5: Add support to match inner packet fields

Add support to match packet fields which are tunneled,
i.e. support matching the header of the inner packet which is the result of
or bit operation of the original header and the IB_FLOW_SPEC_INNER type.

The combination of IB_FLOW_SPEC_INNER | IB_FLOW_SPEC_VXLAN_TUNNEL is not
needed to be checked, because the IB core has this check already.

Signed-off-by: Moses Reuben <mosesr@mellanox.com>
Reviewed-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>