qcacmn: Migrate WMI from shared work queue to dedicated work queue

WMI RX event processing is very critical for WLAN driver and today
we are using kernel's shared event work queue. Shared event work
queue is used by many drivers and if any work submitted in shared
work queue takes longer time to finish then it directly impacts WLAN
control path processing.

Define a dedicated work queue for WMI RX event processing and use
it for WMI RX event handling.

Change-Id: I8ee6ca5b4b20c3357d46f8b56943078a0a76977f
CRs-Fixed: 2029775

wmi_unified_priv.h

@@ -1329,7 +1329,8 @@ struct wmi_unified {
 	void *htc_handle;
 	qdf_spinlock_t eventq_lock;
 	qdf_nbuf_queue_t event_queue;
-	struct work_struct rx_event_work;
+	qdf_work_t rx_event_work;
+	qdf_workqueue_t *wmi_rx_work_queue;
 	int wmi_stop_in_progress;
 #ifdef CONFIG_MCL
 	struct _wmi_abi_version fw_abi_version;