libutilscallstack is private VNDK-SP

The library isn't intented to be exposed to vendors. It is a platform
private library.

Bug: 72471487
Test: Pixel 2016/2017 boots to the UI. Photo editing works.
Change-Id: Ib0479a43d66d988c2f882688240746bed3213dad
diff --git a/libutils/Android.bp b/libutils/Android.bp
index 3bca6c8..2be5d98 100644
--- a/libutils/Android.bp
+++ b/libutils/Android.bp
@@ -157,6 +157,7 @@
 cc_library {
     name: "libutilscallstack",
     defaults: ["libutils_defaults"],
+    vendor_available: false,
 
     srcs: [
         "CallStack.cpp",