vboot: use standard memcmp, memcpy, memset

Originally, we didn't trust the firmware to provide these functions from
a standard library.  Now, with coreboot, we do.

BUG=chromium:611535
BRANCH=none
TEST=make runtests; emerge-kevin coreboot depthcharge

Change-Id: I4e624c40085f2b665275a38624340b2f6aabcf11
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/399120
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>
51 files changed