Remove oamaha related code am: 033e173e3f am: 3141621dc6 am: b760252c4c am: 71860728d6

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2747005

Change-Id: I19296a73626d20c520b67ddb598e7020ede38998
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>