ieee80211: Update generic definitions to latest specs - take #2

Hi,

Following patches update the definitions of the generic ieee80211 stack to the latest versions of the published 802.11x specification suite, and cleans up the long list of defines.

The set of patches is a resubmittal of my earlier patch, with the comments of Jiri Benc and Stephen Hemminger fixed.

The patches need to be applied in order.

Thanks,

Gertjan van Wingerde