net/mlx5e: TC preparation refactoring for routing update event

Following patch in series implement routing update event which requires
ability to modify rule match_to_reg modify header actions dynamically
during rule lifetime. In order to accommodate such behavior, refactor and
extend TC infrastructure in following ways:

- Modify mod_hdr infrastructure to preserve its parse attribute for whole
rule lifetime, instead of deallocating it after rule creation.

- Extend match_to_reg infrastructure with new function
mlx5e_tc_match_to_reg_set_and_get_id() that returns mod_hdr action id that
can be used afterwards to update the action, and
mlx5e_tc_match_to_reg_mod_hdr_change() that can modify existing actions by
its id.

- Extend tun API with new functions mlx5e_tc_tun_update_header_ipv{4|6}()
that are used to updated existing encap entry tunnel header.

Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: Dmytro Linkin <dlinkin@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>