net/sched: act_mirred: Use passed lastuse argument

stats_update callback is called by NIC drivers doing hardware
offloading of the mirred action. Lastuse is passed as argument
to specify when the stats was actually last updated and is not
always the current time.

Fixes: 9798e6fe

 ('net: act_mirred: allow statistic updates from offloaded actions')
Signed-off-by: Paul Blakey <paulb@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>