Fix missing-prototypes warnings

A missing include in helpers.c triggered a bunch of missing-prototypes
warnings.

BUG=None
TEST=Local build with -Wall is now free of warnings

Change-Id: I8d6655ba48abd5cb4f48fa29520f62b076a45690
Reviewed-on: https://chromium-review.googlesource.com/241441
Reviewed-by: Lauri Peltonen <lpeltonen@nvidia.com>
Commit-Queue: Lauri Peltonen <lpeltonen@nvidia.com>
Tested-by: Lauri Peltonen <lpeltonen@nvidia.com>
Reviewed-by: St├ęphane Marchesin <marcheu@chromium.org>
1 file changed