Update kernel to builds 8840540 am: 6d340babb8 am: 2cd8f70372

Original change: https://googleplex-android-review.googlesource.com/c/device/google/cuttlefish_prebuilts/+/19320908

Change-Id: Ib596a295eca9087f83c9022a5afd3d6acff81ce9
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>