evs: Use ui::LayerStack

Bug: 182939859
Test: Build
Change-Id: I8d21e3a0bea81a351fb0c48882f92eb8c784ad80
diff --git a/automotive/evs/1.1/vts/functional/VtsHalEvsV1_1TargetTest.cpp b/automotive/evs/1.1/vts/functional/VtsHalEvsV1_1TargetTest.cpp
index 8cc1882..e1b9729 100644
--- a/automotive/evs/1.1/vts/functional/VtsHalEvsV1_1TargetTest.cpp
+++ b/automotive/evs/1.1/vts/functional/VtsHalEvsV1_1TargetTest.cpp
@@ -630,7 +630,7 @@
         ASSERT_GT(height, 0);
 
         android::ui::DisplayState* pState = (android::ui::DisplayState*)state.data();
-        ASSERT_NE(pState->layerStack, -1);
+        ASSERT_NE(pState->layerStack, android::ui::INVALID_LAYER_STACK);
     });
 
     // Test each reported camera