qcacmn: Remove unnecessary locking during WMI detach

HOST driver unload sequence does following
   1) Kill WLAN tasklet
   2) Disable CE interrupts
   3) Flush WMI RX work
Hence its unncessory to acquire eventq_lock as no one
will be using the shared resource during wmi detach.

Change-Id: I5c549358aeefc460c794c35659915d3b966c7350
CRs-Fixed: 1021376

wmi_unified.c

@@ -2221,7 +2221,6 @@ void wmi_unified_detach(struct wmi_unified *wmi_handle)
 
 	wmi_debugfs_remove(wmi_handle);
 
-	qdf_spin_lock_bh(&wmi_handle->eventq_lock);
 	buf = qdf_nbuf_queue_remove(&wmi_handle->event_queue);
 	while (buf) {
 		qdf_nbuf_free(buf);
@@ -2232,7 +2231,6 @@ void wmi_unified_detach(struct wmi_unified *wmi_handle)
 	wmi_log_buffer_free(wmi_handle);
 #endif
 
-	qdf_spin_unlock_bh(&wmi_handle->eventq_lock);
 	qdf_spinlock_destroy(&wmi_handle->eventq_lock);
 	qdf_spinlock_destroy(&wmi_handle->ctx_lock);
 	OS_FREE(wmi_handle);