If set_hostapd_nr config flag is set, dawn will insert the nr reports
to allow the hostapd to answer to nr requests from clients.
Improve the synchronization of rcpi and rsni in the network.
Further, clients with bad 802.11k were sending beacon reports with
bssid 00:00:00:00:00:00. Catch those corner cases.
Signed-off-by: Nick Hainke <vincent@systemli.org>