Merge branch 'net-make-kobj_type-structures-constant'

Thomas Weißschuh says:

====================
net: make kobj_type structures constant

Since commit ee6d3dd4ed48 ("driver core: make kobj_type constant.")
the driver core allows the usage of const struct kobj_type.

Take advantage of this to constify the structure definitions to prevent
modification at runtime.
====================

Link: https://lore.kernel.org/r/20230211-kobj_type-net-v2-0-013b59e59bf3@weissschuh.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>