Merge "Default to arch-specific u-boot implementation for bootloader." into main am: 39c9325fab

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Virtualization/+/3264073

Change-Id: I5a3f00bab76d30ee4bd6046279885fe18ea30df0
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>