Mark VINTF AIDL w/ Java as platform_apis.

Since this requires platform-only APIs (markVintfStability).

Bug: 139325468
Test: use vibrator callback from Java
Change-Id: Ic675c82973e04f80db67da1b9c69964ef33b35f7
diff --git a/vibrator/aidl/Android.bp b/vibrator/aidl/Android.bp
index e26041a..1eec1da 100644
--- a/vibrator/aidl/Android.bp
+++ b/vibrator/aidl/Android.bp
@@ -6,6 +6,9 @@
     ],
     stability: "vintf",
     backend: {
+        java: {
+            platform_apis: true,
+        },
         ndk: {
             vndk: {
                 enabled: true,