net_sched: act: annotate data-races in tcf_lastuse_update() and tcf_tm_dump()

tcf_tm_dump() reads fields that can be changed concurrently,
and tcf_lastuse_update() might race against itself.

Add READ_ONCE() and WRITE_ONCE() annotations.

Fetch jiffies once in tcf_tm_dump().

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250709090204.797558-2-edumazet@google.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>