rust: add OWNERS am: 7ca80d47b1 am: 9a3cce280e

Original change: https://android-review.googlesource.com/c/platform/system/tools/mkbootimg/+/3327442

Change-Id: Ic9c5b5cec35db974d41790b42dee19cd7595c7bd
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>