net/sched: cls_flower: Hardware offloaded filters statistics support

Introduce a new command in ndo_setup_tc() for hardware offloaded
filters, to call the NIC driver, and make it update the statistics.
This will be done before dumping the filter and its statistics.

Signed-off-by: Amir Vadai <amirva@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>