Revert "Audio V4: Split system and vendor Audio.h"

This reverts commit 49c56de516b4e9556ae1b0af0ccfa7d695f5807b.

Reason for revert: Breaks the build of multiple devices

Change-Id: Iebd868467948b8afa5907462ccc0720cd9c4871e
diff --git a/audio/common/all-versions/util/Android.bp b/audio/common/all-versions/util/Android.bp
index 7132667..5d33a3a 100644
--- a/audio/common/all-versions/util/Android.bp
+++ b/audio/common/all-versions/util/Android.bp
@@ -1,7 +1,10 @@
 cc_library_headers {
     name: "android.hardware.audio.common.util@all-versions",
     defaults: ["hidl_defaults"],
-    vendor: true,
+    vendor_available: true,
+    vndk: {
+        enabled: true,
+    },
 
     export_include_dirs: ["include"],
 }