[MAC80211]: Remove overly sticky averaging filters for rssi, signal, noise

The current version of wireless statistics contains a bug in the averaging
that makes the numbers be too sticky and not react to small changes. This
patch removes all averaging.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Jiri Benc <jbenc@suse.cz>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>