qcacld-3.0: Flush the scan result only in lost link case

Currently the driver flushes the scan entry in the scan
db for the BSSID which it was connected to in deauth, disassoc
and lostlink case.
In case of disassoc, and deauth, ap is still alive, hence
there is a chance for connection, but in lostlink case
there is no chance as the AP is switched off.
So if the supplicant finds the scan result in the scan
cache, it would try connect with this, but since the AP is not
present, and cannot service anymore, it would result to a
failed connect attempt.
After several failure attempts, supplicant would blacklist the
AP for some time.
If the AP is alive again, the DUT cannot connect to it since
it is blacklisted. Hence this situation leads to blacklisting
a AP which did not send any assoc reject, and can service the
DUT.

Fix is to clear the scan cache so that supplicant cannot try to
send connect request for this AP to the driver, hence there
would be no point to blacklist the AP.
This would ensure the wireless connection with this AP in
future.

Change-Id: I14fb36ef588856750917d83c32644b135186def9
CRs-Fixed: 2525539

core/hdd/src/wlan_hdd_assoc.c

@@ -1858,9 +1858,7 @@ static QDF_STATUS hdd_dis_connect_handler(struct hdd_adapter *adapter,
 		hdd_debug("roam_result: %d", roam_result);
 
 		/* clear scan cache for Link Lost */
-		if (eCSR_ROAM_RESULT_DEAUTH_IND == roam_result ||
-		    eCSR_ROAM_RESULT_DISASSOC_IND == roam_result ||
-		    eCSR_ROAM_LOSTLINK == roam_status) {
+		if (eCSR_ROAM_LOSTLINK == roam_status) {
 			wlan_hdd_cfg80211_unlink_bss(adapter,
 				sta_ctx->conn_info.bssid.bytes,
 				sta_ctx->conn_info.ssid.SSID.ssId,