Revert "libsystem_headers: export libaudio_system_headers"

This reverts commit c83ea95654c4cf8f9bb60b9e69cac7f3ed32b14f.

Change-Id: I86d89381257e975654bbd0d4e71c35ca77e87228
diff --git a/libsystem/Android.bp b/libsystem/Android.bp
index e92fe63..846a585 100644
--- a/libsystem/Android.bp
+++ b/libsystem/Android.bp
@@ -2,10 +2,6 @@
     name: "libsystem_headers",
     vendor_available: true,
     host_supported: true,
-
-    header_libs: ["libaudio_system_headers"],
-    export_header_lib_headers: ["libaudio_system_headers"],
-
     export_include_dirs: ["include"],
 
     target: {