qcacmn: Fix memory leaks in scan start and stop requests

-Fix memory leaks in scan start and stop request by freeing the
request if posting to scheduler fails.
-Populate scan event id based on target.

Change-Id: I169c4f3c141dc1af48954788dc74d235afd59c9e
CRs-Fixed: 1095299

target_if/scan/src/target_if_scan.c

@@ -29,6 +29,18 @@
 #include <wlan_scan_tgt_api.h>
 #include <target_if.h>
 
+#ifdef CONFIG_MCL
+inline uint32_t get_scan_event_id(void)
+{
+	return WMI_SCAN_EVENTID;
+}
+#else
+inline uint32_t get_scan_event_id(void)
+{
+	return wmi_scan_event_id;
+}
+#endif
+
 static inline struct wlan_lmac_if_scan_rx_ops *
 target_if_scan_get_rx_ops(struct wlan_objmgr_psoc *psoc)
 {
@@ -85,8 +97,11 @@ target_if_scan_event_handler(ol_scn_t scn, uint8_t *data, uint32_t datalen)
 QDF_STATUS
 target_if_scan_register_event_handler(struct wlan_objmgr_psoc *psoc, void *arg)
 {
+	uint32_t scan_event_id;
+
+	scan_event_id = get_scan_event_id();
 	return wmi_unified_register_event_handler(psoc->tgt_if_handle,
-		wmi_scan_event_id, target_if_scan_event_handler,
+		scan_event_id, target_if_scan_event_handler,
 		WMI_RX_UMAC_CTX);
 }
 
@@ -94,8 +109,11 @@ QDF_STATUS
 target_if_scan_unregister_event_handler(struct wlan_objmgr_psoc *psoc,
 		void *arg)
 {
+	uint32_t scan_event_id;
+
+	scan_event_id = get_scan_event_id();
 	return wmi_unified_unregister_event_handler(psoc->tgt_if_handle,
-		wmi_scan_event_id);
+		scan_event_id);
 }
 
 QDF_STATUS