qcacld-3.0: Fix memory leak in tx flow control timer

qcacld-2.0 to qcacld-3.0 propagation

TX flow control timer initialized when STATION interface is created.
During IBSS startup, STATION interface is changed to ADHOC type.
TX flow control timer is not required, so close tx flow control
and destroy timer.

Change-Id: Id9c440638964fb3ab0e95d8a7c747708886a94ff
CRs-Fixed: 882821

core/hdd/src/wlan_hdd_cfg80211.c

@@ -5540,6 +5540,7 @@ static int __wlan_hdd_cfg80211_change_iface(struct wiphy *wiphy,
 
 		case NL80211_IFTYPE_ADHOC:
 			wlan_hdd_tdls_exit(pAdapter);
+			hdd_deregister_tx_flow_control(pAdapter);
 			hddLog(LOG1, FL("Setting interface Type to ADHOC"));
 			wlan_hdd_change_iface_to_adhoc(ndev, pRoamProfile,
 						       type);