Enable Rust build of android.hardware.media.bufferpool2.

This is a prerequisite for android.hardware.media.c2, which I'm
splitting out to a separate CL to simplify merging.

Bug: 295245772
Change-Id: I1ab9ed45b0b500065c0f18b810c3aa266878b80f

common/fmq/aidl/Android.bp

@@ -43,8 +43,9 @@ aidl_interface {
             min_sdk_version: "29",
         },
         rust: {
-            // FMQ is not supported in the rust backend
-            enabled: false,
+            // FMQ is not supported in the rust backend, but we need this AIDL interface for
+            // HardwareBuffer.
+            enabled: true,
         },
     },
     frozen: true,

media/bufferpool/aidl/Android.bp

@@ -46,6 +46,9 @@ aidl_interface {
             ],
             min_sdk_version: "29",
         },
+        rust: {
+            enabled: true,
+        },
     },
     versions_with_info: [
         {