futility: add separate check function for VPbublicKey

Provide a PublicKeyLooksOkay() function to sanity-check VbPublicKey structs.
This was just part of PublicKeyRead(), but I want to separate the reading
from the checking.

BUG=chromium:224734
BRANCH=ToT
TEST=make runtests

Change-Id: I1dd808e623e2a7fdc2789e02305619111a7b01e6
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/214621
Reviewed-by: Randall Spangler <rspangler@chromium.org>
2 files changed