gru: Drop pre-unibuild support

Kevin & bob both migrated to unibuild, so this code is now unused.

BUG=b:216515833
TEST=compiles

Change-Id: Ia51a1731c7a7d12e83b8c05669395408aba1cd7d
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/mosys/+/3428539
Tested-by: Jack Rosenthal <jrosenth@chromium.org>
Auto-Submit: Jack Rosenthal <jrosenth@chromium.org>
Reviewed-by: Jacob Rasmussen <jacobraz@google.com>
Commit-Queue: Jacob Rasmussen <jacobraz@google.com>
3 files changed