Merge branch 'fix-bpf-qdisc-bugs-and-clean-up'

Amery Hung says:

====================
Fix bpf qdisc bugs and clean up

This patchset fixes the following bugs in bpf qdisc and clean up the
selftest.

- A null-pointer dereference can happen in qdisc_watchdog_cancel() if
  the timer is not initialized when 1) .init is not defined by user so
  init prologue is not generated. 2) .init fails and qdisc_create()
  calls .destroy

- bpf qdisc fails to attach to mq/mqprio when being set as the default
  qdisc due to failed qdisc_lookup() in init prologue

v2
- Rebase to bpf-next/net
- Fix erroneous commit messages
- Fix and simplify selftests cleanup
  v1: https://lore.kernel.org/bpf/20250501223025.569020-1-ameryhung@gmail.com/
====================

Link: https://patch.msgid.link/20250502201624.3663079-1-ameryhung@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>