o add ic_curchan and use it uniformly for specifying the current
channel instead of overloading ic->ic_bss->ni_chan (or in some
drivers ic_ibss_chan)
o add ieee80211_scanparams structure to encapsulate scanning-related
state captured for rx frames
o move rx beacon+probe response frame handling into separate routines
o change beacon+probe response handling to treat the scan table
more like a scan cache--look for an existing entry before adding
a new one; this combined with ic_curchan use corrects handling of
stations that were previously found at a different channel
o move adhoc neighbor discovery by beacon+probe response frames to
a new ieee80211_add_neighbor routine
Reviewed by: avatar
Tested by: avatar, Michal Mertl
MFC after: 2 weeks
7d1366bf6d