Merge branch 'net-sched-cls_u32-use-proper-refcounts'

Pedro Tammela says:

====================
net/sched: cls_u32: use proper refcounts

In u32 we are open coding refcounts of hashtables with integers which is
far from ideal. Update those with proper refcount and add a couple of
tests to tdc that exercise the refcounts explicitly.
====================

Link: https://lore.kernel.org/r/20231114141856.974326-1-pctammela@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>