cfg80211: add KHz variants of frame RX API

Drivers may wish to report the RX frequency in units of
KHz. Provide cfg80211_rx_mgmt_khz() and wrap it with
cfg80211_rx_mgmt() so exisiting drivers which can't report
KHz anyway don't need to change. Add a similar wrapper for
cfg80211_report_obss_beacon() so the frequency units stay
somewhat consistent.

This doesn't actually change the nl80211 API yet.

Signed-off-by: Thomas Pedersen <thomas@adapt-ip.com>
Link: https://lore.kernel.org/r/20200430172554.18383-2-thomas@adapt-ip.com


[fix mac80211 calling the non-khz version of obss beacon report,
 drop trace point name changes]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>