vboot_reference: Provide crossystem interface stubs for mips

BUG=chromium:358418
TEST=emerge-mipsel-o32-generic vboot_reference now builds.
BRANCH=none

Change-Id: Ia1414dfdef00c5b22ed0971fad814ef761b32b86
Reviewed-on: https://chromium-review.googlesource.com/193050
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Tested-by: Gaurav Shah <gauravsh@chromium.org>
Commit-Queue: Gaurav Shah <gauravsh@chromium.org>
1 file changed