cbmem: rename vdat to chromeos_acpi

There is a confusingly named section in cbmem called vdat.
This section holds a data structure called chromeos_acpi_t,
which exposes some system information to the Chrome OS
userland utility crossystem.

Within the chromeos_acpi_t structure, there is a member
called vdat.  This (currently) holds a VbSharedDataHeader.

Rename the outer vdat to chromeos_acpi to make its purpose
clear, and prevent the bizarreness of being able to access

Additionally, disallow external references to the
chromeos_acpi data structure in gnvs.c.

TEST=emerge-eve coreboot, run on eve

Change-Id: Ia74e58cde21678f24b0bb6c1ca15048677116b2e
Signed-off-by: Joel Kitching <kitching@google.com>
Reviewed-on: https://review.coreboot.org/27888
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
8 files changed