[sf] Only trace rebuildLayerStacks if there are changes

Clean up perfetto traces  to only show
tags when they are interesting.

Bug: 292225846
Test: open trace in perfetto
Change-Id: I1e3744abb08c7a3b34244db8ce8be5299cf86b19
diff --git a/services/surfaceflinger/CompositionEngine/src/Output.cpp b/services/surfaceflinger/CompositionEngine/src/Output.cpp
index 1205a2c..b1b5708 100644
--- a/services/surfaceflinger/CompositionEngine/src/Output.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Output.cpp
@@ -469,15 +469,14 @@
 
 void Output::rebuildLayerStacks(const compositionengine::CompositionRefreshArgs& refreshArgs,
                                 LayerFESet& layerFESet) {
-    ATRACE_CALL();
-    ALOGV(__FUNCTION__);
-
     auto& outputState = editState();
 
     // Do nothing if this output is not enabled or there is no need to perform this update
     if (!outputState.isEnabled || CC_LIKELY(!refreshArgs.updatingOutputGeometryThisFrame)) {
         return;
     }
+    ATRACE_CALL();
+    ALOGV(__FUNCTION__);
 
     // Process the layers to determine visibility and coverage
     compositionengine::Output::CoverageState coverage{layerFESet};