arc: Include missing vector header

With the latest LLVM, we encountered this missing <vector>
include that should have been introduced along with
https://chromium-review.googlesource.com/c/aosp/platform/system/keymaster/+/6058651

Caught because we encountered the error here:
https://paste.googleplex.com/5661780354007040

BUG=b:368393962
TEST=Built locally for Brya

Change-Id: I20e8c48763957423f8dca11d9d3f7dc959861433
Reviewed-on: https://chromium-review.googlesource.com/c/aosp/platform/system/keymaster/+/6196346
Commit-Queue: Jordan Abrahams-Whitehead <[email protected]>
Tested-by: Jordan Abrahams-Whitehead <[email protected]>
Reviewed-by: Vaibhav Raheja <[email protected]>
1 file changed