b53.rst: is the 5325/5365 "no tagging support" section still accurate?

Hi Álvaro,

Documentation/networking/dsa/b53.rst still lists 5325/5365 under
"Configuration without tagging support", saying they "support a
different tag format that is not supported yet". But
b53_get_tag_protocol() assigns them DSA_TAG_PROTO_BRCM_LEGACY_FCS,
which seems to have an implementation in net/dsa/tag_brcm.c
(brcm_leg_fcs_tag_xmit). This looks like it's been true since
c3cf059a4d41.

Separately, ds->untag_bridge_pvid (b53_common.c) is only set when
tag_protocol == DSA_TAG_PROTO_NONE -- which I guess no longer applies
to 5325/5365 -- so the VLAN workaround described right after
(removing the default VLAN 1) may not apply to them either anymore.

Is the doc just stale on both counts, or is there a reason 5325/5365
still belong in that section in practice? I don't have this hardware
to test against. Happy to send a fix once I know which parts still
hold.

Thanks,
Christian