Start dealing with Element ID Extension present (IE T=255) and start
parsing elemets from the Element ID Extension set.
Namely also (partially) decode HE_CAPA, HE_OPER, MU_EDCA_PARAM_SET,
and as well as SUP_OP_CLASS.
For length reasons also rename UNKNOWN_ELEMID_%d to ELEMID_%d.
Sponsored by: The FreeBSD Foundation
MFC after: 3 days