This patch fixes needless probe request caused by zero value in
sta->last_rx inside ieee80211_associated flow
Signed-off-by: Ron Rindjunsky <ron.rindjunsky@intel.com> Signed-off-by: Tomas Winkler <tomas.winkler@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>