RMA auth uses X25519 to generate a relatively small challenge and
response.
Currently, nothing calls the rma_auth code. We'll need console and
TPM vendor commands to do so.
BUG=b:37952913
BRANCH=none
TEST=make buildall
Change-Id: Iec7f2d0e3dc8243f79b009ead16bb3ba9f1bef9d
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/544184
