The original list of IEs got expanded from TLV to TLextTV.
If the T matches 255 then we have a second list of IEs where the
meaning of TL stays the same. That means the 1 octet extT is part
of the length and the value starts at ie+3.
Start populating the list with IEEE802.11-2020 and 802.11ax-2021
values.
They will be initially used to start decoding some of the announced IEs
for ifconfig [-v] list (scan|sta). That should help users with
AX-enabled APs to see this (rather than no or UNKNOWN_ELEMID_255 and
make debugging easier once we implement 11ax.
Sposored by: The FreeBSD Foundation
MFC after: 3 days