wlan: Send disconnect event to upper layers upon disconnect

Indicate disconnect event to nl80211 and thereby to the supplicant
by invoking cfg80211_disconnect upon disconnect as kernel 3.11 onward
releases will not indicate the same to upper layers.

Call to cfg80211_disconnect also signifies whether disconnect is
triggered by the supplicant or received from the AP by setting the
"from_ap" flag accordingly.

Change-Id: I55028533ebbf03910755da1b35c2fa57d97ce43b
CRs-Fixed: 1016872
diff --git a/CORE/HDD/src/wlan_hdd_main.c b/CORE/HDD/src/wlan_hdd_main.c
index 48cc97b..915b038 100644
--- a/CORE/HDD/src/wlan_hdd_main.c
+++ b/CORE/HDD/src/wlan_hdd_main.c
@@ -9198,8 +9198,8 @@
                pAdapter->sessionCtx.station.hdd_ReassocScenario = VOS_FALSE;
 
                /* indicate disconnected event to nl80211 */
-               cfg80211_disconnected(pAdapter->dev, WLAN_REASON_UNSPECIFIED,
-                                     NULL, 0, GFP_KERNEL); 
+               wlan_hdd_cfg80211_indicate_disconnect(pAdapter->dev, true,
+                                                     WLAN_REASON_UNSPECIFIED);
             }
             else if (eConnectionState_Connecting == connState)
             {