Integrate the flash key-value store code into cgpt.

Integrates the FTS driver into cgpt. This driver is binary-format compatible
with the linux driver for interoperabiilty. The cgpt changes load & store a
hex-encoded mtd partition table in the FTS; we need some sort of encoding
because FTS only stores NUL-terminated strings.

Currently, the mtd code paths aren't executed in cgpt, only in the tests. It's
also not hooked up to the vboot code yet, we will need to do that eventually.

BUG=chromium:221745
TEST=new unit test added
BRANCH=none

Change-Id: I94eb0389d29aca0beb9d9a644465c7d86161b3c2
Original-Change-Id: I9fe2fa91b666572563426adb8fa9d426f9b60bbf
Reviewed-on: https://gerrit.chromium.org/gerrit/46796
Commit-Queue: Albert Chaulk <achaulk@chromium.org>
Reviewed-by: Albert Chaulk <achaulk@chromium.org>
Tested-by: Albert Chaulk <achaulk@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/49789
7 files changed