net: lan966x: Add ES0 VCAP model

Provide ES0 (egress stage 0) VCAP model for lan966x.
This provides rewriting functionality in the gress path.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>