Set root elements for xsd_config modules

This reduces the code size by not generating unnecessary code for
non-root elements.

Bug: 283700992
Test: m
Change-Id: I23bd5c2a0ccc40fded3ca08155ead5f4680c2ed9
diff --git a/bluetooth/audio/utils/Android.bp b/bluetooth/audio/utils/Android.bp
index 914d2b2..2cba61e 100644
--- a/bluetooth/audio/utils/Android.bp
+++ b/bluetooth/audio/utils/Android.bp
@@ -93,4 +93,5 @@
     srcs: ["le_audio_codec_capabilities/le_audio_codec_capabilities.xsd"],
     package_name: "aidl.android.hardware.bluetooth.audio.setting",
     api_dir: "le_audio_codec_capabilities/schema",
+    root_elements: ["leAudioOffloadSetting"],
 }