volume listener: provide more debugging info when effect desc is null

Since this is some abnormal condition, dump the volume effects list
regardless of the 'dumping_enable' flag state.

Bug: 63780779
Test: more debug info is provided when the error condition encountered
Change-Id: I4523414cbe4a9da1bcea6e181e115053cdcee9a9
diff --git a/post_proc/volume_listener.c b/post_proc/volume_listener.c
index d4aa79f..cb83808 100644
--- a/post_proc/volume_listener.c
+++ b/post_proc/volume_listener.c
@@ -770,9 +770,7 @@
     if (recv_contex->desc == NULL) {
         ALOGE("%s: Got NULL descriptor, session %u, stream type %u",
                 __func__, session_id, stream_type);
-        if (dumping_enabled) {
-            dump_list_l();
-        }
+        dump_list_l();
         pthread_mutex_unlock(&vol_listner_init_lock);
         return status;
     }