qcacld-3.0: Fix typo "existance"

Replace typo "existance" with correct spelling "existence".

Change-Id: I58be5bc661c42b61e7e161d7641e6c39edc0bf7c
CRs-Fixed: 2238297

core/hdd/src/wlan_hdd_hostapd.c

@@ -2121,7 +2121,7 @@ QDF_STATUS hdd_hostapd_sap_event_cb(tpSap_Event pSapEvent,
 				 * After Kernel 4.0, it's no longer need to set
 				 * STATION_INFO_ASSOC_REQ_IES flag, as it
 				 * changed to use assoc_req_ies_len length to
-				 * check the existance of request IE.
+				 * check the existence of request IE.
 				 */
 				sta_info->filled |= STATION_INFO_ASSOC_REQ_IES;
 #endif