net: dsa: felix: add stream gate settings for psfp

This patch adds stream gate settings for PSFP. Use SGI table to store
stream gate entries. Disable the gate entry when it is not used by any
stream.

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