Mark some aidl_interface modules as unstable

With b/152655547, all aidl_interface modules are considered as stable
unless it is explicitly with "unstable: true". This change marks the
aidl_interface that are not used across updatable module bounraries
as unstable, so that the build system does not run the API
dumping/checking on them.

Bug: 152655547
Test: m
Change-Id: Ic16f45803a4532ffd818e74e3ca4b90f788113cc
diff --git a/Android.bp b/Android.bp
index 174567b..160a220 100644
--- a/Android.bp
+++ b/Android.bp
@@ -111,6 +111,7 @@
 
 aidl_interface {
     name: "gsi_aidl_interface",
+    unstable: true,
     srcs: [":gsiservice_aidl"],
     local_include_dir: "aidl",
     backend: {