[automerger skipped] Update rustflags to work with new hal_v4 types am: b515705780 -s ours

am skip reason: Merged-In I5ebea2568301d6bc61783f18829ae0fb386a7fc3 with SHA-1 4daa65d001 is already in history

Original change: https://android-review.googlesource.com/c/trusty/lib/+/3328499

Change-Id: Ib5b08cf358fde26b5a530c2bc399b97770e7ad61
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>