net: dsa: b53: Turn off Broadcom tags for more switches

Models such as BCM5395/97/98 and BCM53125/24/53115 and compatible require that
we turn on managed mode to actually act on Broadcom tags, otherwise they just
pass them through on ingress (host -> switch) and don't insert them in egress
(switch -> host). Turning on managed mode is simple, but requires us to
properly support ARL misses on multicast addresses which is a much more
involved set of changes not suitable for a bug fix for this release.

Reported-by: Jochen Friedrich <jochen@scram.de>
Fixes: 7edc58d6 ("net: dsa: b53: Turn on Broadcom tags")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>