Merge branch 'dsa-port-fast-ageing'

Vivien Didelot says:

====================
net: dsa: add port fast ageing

Today the DSA drivers are in charge of flushing the MAC addresses
associated to a port when its STP state changes from Learning or
Forwarding, to Disabled or Blocking or Listening.

This makes the drivers more complex and hides this generic switch logic.

This patchset introduces a new optional port_fast_age operation to
dsa_switch_ops, to move this logic to the DSA layer and keep drivers
simple. b53 and mv88e6xxx are updated accordingly.
====================

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>