Update kernel to builds 9480296

git log --first-parent -100 --oneline --no-decorate 955a8699b86a..955a8699b86a:

Test: treehugger
Bug: 262792308
Change-Id: I94f4db784ec8920e31a783fb09cde543e9017594
diff --git a/microdroid/kernel/arm64/prebuilt-info.txt b/microdroid/kernel/arm64/prebuilt-info.txt
new file mode 100644
index 0000000..5df89ba
--- /dev/null
+++ b/microdroid/kernel/arm64/prebuilt-info.txt
@@ -0,0 +1,3 @@
+{
+    "kernel-build-id": 9480296
+}