Initial 802.11k Neighbor List implementation.

1. Process WLAN_ACTION_RADIO_MEASUREMENT action frames
   for WLAN_RRM_NEIGHBOR_REPORT_REQUEST, send back an
   WLAN_RRM_NEIGHBOR_REPORT_RESPONSE.

2. Add neighbor_ap_list_file to hostapd.conf, a file
   containing one line per AP to be included in the Neighbor
   Report Response.

3. In hostapd.conf, make radio_measurements available
   even if !TESTING. This is moving from an experimental
   feature to production.

Note that clients will only send Neighbor Report Requests
when the AP has advertised support for Radio Management in
its beacons and probe responses. This requires the following
settings in hostapd.conf:
  radio_measurements=1
  local_pwr_constraint=3  (or some value, not necessarily 3)
  spectrum_mgmt_required=1
  neighbor_ap_list_file=/tmp/waveguide/APs.wlan#

Change-Id: I38b36836e7bb9b73d59ffbbcbef4608527c3d34f
7 files changed