Merge branch 'net-constify-struct-class-usage'

Ricardo B. Marliere says:

====================
net: constify struct class usage

This is a simple and straight forward cleanup series that aims to make the
class structures in net constant. This has been possible since 2023 [1].

[1]: https://lore.kernel.org/all/2023040248-customary-release-4aec@gregkh/
====================

Link: https://lore.kernel.org/r/20240302-class_cleanup-net-next-v1-0-8fa378595b93@marliere.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>