vboot: more complete EC sync testing

Add more checks of updated and protected function calls.

Check that VB2_SD_STATUS_EC_SYNC_COMPLETE is always set,
regardless of whether EC sync actually runs.

Only perform action in mock functions when return value
is non-error.

BUG=b:124141368, chromium:1042135
TEST=make clean && make runtests
BRANCH=none

Change-Id: I2e7d9770f4c105d372c6e068a95b4fbc78a085c7
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/2004248
Tested-by: Joel Kitching <kitching@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Commit-Queue: Joel Kitching <kitching@chromium.org>
2 files changed