Add support for configuring PSFP flow-meters (IEEE 802.1Q-2018,
8.6.5.1.3).

The VCAP CLM (VCAP IS0 ingress classifier) classifies streams,
identified by ISDX (Ingress Service Index, frame metadata), and maps
ISDX to flow-meters. SDLB's provide the flow-meter parameters.
Signed-off-by: NDaniel Machon <daniel.machon@microchip.com>
Reviewed-by: NSimon Horman <simon.horman@corigine.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>