prima: extscan: Update extscan capabilities.

1. Update structure tpSirEXTScanCapabilitiesEvent with
   more capabilities.
2. Add structure hdd_ext_scan_context which is used for
   implementing blocking mechanism.
3. Add blocking mechanism to send extscan capabilities
   to the upper layer in same context.
4. Remove Mtrace enum TRACE_CODE_SME_RX_HDD_EXTSCAN_
   GET_CAPABILITIES to avoid multiple Mtrace messages in
   sme_EXTScanGetCapabilities

Change-Id: If98d4e421098d558f1ba6f70a6e4d873d5c4463a
CRs-Fixed: 834122
diff --git a/CORE/HDD/src/wlan_hdd_main.c b/CORE/HDD/src/wlan_hdd_main.c
index 396f651..ea3a2f8 100755
--- a/CORE/HDD/src/wlan_hdd_main.c
+++ b/CORE/HDD/src/wlan_hdd_main.c
@@ -9592,6 +9592,10 @@
    init_completion(&pHddCtx->driver_crda_req);
 #endif
 
+#ifdef WLAN_FEATURE_EXTSCAN
+   init_completion(&pHddCtx->ext_scan_context.response_event);
+#endif /* WLAN_FEATURE_EXTSCAN */
+
    spin_lock_init(&pHddCtx->schedScan_lock);
 
    hdd_list_init( &pHddCtx->hddAdapters, MAX_NUMBER_OF_ADAPTERS );