ANI can't be turned on/off dynamically yet, but the calculation
of the calibration period is wrong anyway. This patch fixes it.
Reported-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NSujith <Sujith.Manoharan@atheros.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>