dql: annotate data-races around dql->last_obj_cnt

dql->last_obj_cnt is read/written from different contexts,
without any lock synchronization.

Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Joe Damato <jdamato@fastly.com>
Link: https://patch.msgid.link/20241029191425.2519085-1-edumazet@google.com


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