wlcore: do not report noise level in get survey op

The get survey op expects the low level driver to report
the noise level for a a given channel.

The noise calculated in wlcore is (rssi-snr/2), but since
the snr reported by the FW is a derivative from the rssi
this calculation is useless, and should not be reported
to the user space.

Reporting incorrect noise, results in the wpa_supplicant
miscalculating the roaming candidate priority, thus causing
a situation where an AP with a lower rssi level would be
chosen over a better AP.
Signed-off-by: Yoni Divinsky <yoni.divinsky@ti.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>

drivers/net/wireless/ti/wlcore/main.c

@@ -4108,16 +4108,13 @@ static u64 wl1271_op_get_tsf(struct ieee80211_hw *hw,
 static int wl1271_op_get_survey(struct ieee80211_hw *hw, int idx,
 				struct survey_info *survey)
 {
-	struct wl1271 *wl = hw->priv;
 	struct ieee80211_conf *conf = &hw->conf;
 
 	if (idx != 0)
 		return -ENOENT;
 
 	survey->channel = conf->channel;
-	survey->filled = SURVEY_INFO_NOISE_DBM;
-	survey->noise = wl->noise;
-
+	survey->filled = 0;
 	return 0;
 }