qcacld-3.0: prevent double free of iface staKeyParams

Memory pointed by stakeyparams is not made NULL after
freeing in wma_set_stakey. This results in double free
during wma_add_bss_sta.

Change-Id: Ifa24d536e116be60f572d9926a511f9f498e6696
CRs-Fixed: 2463399

core/wma/src/wma_dev_if.c

@@ -5520,6 +5520,7 @@ static void wma_add_sta_req_sta_mode(tp_wma_handle wma, tpAddStaParams params)
 		if (iface->staKeyParams) {
 			wma_set_stakey(wma,
 				       (tpSetStaKeyParams) iface->staKeyParams);
+			iface->staKeyParams = NULL;
 		}
 	}
 	maxTxPower = params->maxTxPower;