This WIP just redefines the struct ieee80211req_key used in key get/set
ioctl calls to a separate set of values. The eventual goal is to fully
separate out the ioctl API from the internal key definition sizes so
things like 256 / 384 bit key infrastructure can be included without
needing to also break the default userland ABI.
Note this diff is a WIP - I haven't yet updated the ioctl key get and
set functions themselves to take the copy sizes into account when
copying the key and MIC contents. I will also need to ensure any
unused buffer contents are bzero'ed out rather than copied and leaked.