net: dsa: felix: support psfp filter on vsc9959

VSC9959 supports Per-Stream Filtering and Policing(PSFP) that complies
with the IEEE 802.1Qci standard. The stream is identified by Null stream
identification(DMAC and VLAN ID) defined in IEEE802.1CB.

For PSFP, four tables need to be set up: stream table, stream filter
table, stream gate table, and flow meter table. Identify the stream by
parsing the tc flower keys and add it to the stream table. The stream
filter table is automatically maintained, and its index is determined by
SGID(flow gate index) and FMID(flow meter index).

Signed-off-by: Xiaoliang Yang <xiaoliang.yang_1@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>