Make userfaultfd-sys available to product and vendor am: cff16f5840

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/userfaultfd-sys/+/2476206

Change-Id: Iaa3cf64f46cc6d8aa7b5b06eeeeab55ab5848a7b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>