No need for #pragma once in bindgen header. am: 1ae7385469 am: b1e48a0e15

Original change: https://android-review.googlesource.com/c/platform/system/librustutils/+/2584505

Change-Id: Ib0bd452f280fdc6a8cf155854a263b1a040a4ce8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>