Merge branch 'net-dsa-b53-Add-support-for-MDB'

Florian Fainelli says:

====================
net: dsa: b53: Add support for MDB

This patch series adds support for programming multicast database
entries on b53 and bcm_sf2. This is extracted from a previously
submitted series that added managed mode support, but these patches are
usable in isolation. The larger series still needs to be reworked.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>