Disable the rust backend of android.hardware.media.c2

There are currently no users of it. Enabling it will require adding rust
support for the android.os.Surface type that uses ANativeWindow
underneath.

Test: m
Bug: 315556623
Change-Id: Ib9954b1bf476b391919db994bc2dc1483d972670
diff --git a/media/c2/aidl/Android.bp b/media/c2/aidl/Android.bp
index 3c0915d..84cb382 100644
--- a/media/c2/aidl/Android.bp
+++ b/media/c2/aidl/Android.bp
@@ -42,11 +42,8 @@
             ],
         },
         rust: {
-            min_sdk_version: "31",
-            enabled: true,
-            additional_rustlibs: [
-                "libnativewindow_rs",
-            ],
+            // No users, and no rust implementation of android.os.Surface yet
+            enabled: false,
         },
     },
 }