mb/google/volteer: Add overridetree.cb for volteer variant

Instead of only using the baseboard devicetree add a placeholder
overridetree for volteer and refer to it in Kconfig.

This will allow us to add the volteer specific devices here instead
of at the baseboard level.

BUG=b:146482091

Signed-off-by: Duncan Laurie <dlaurie@google.com>
Change-Id: I7788a5473fc2275a9791fb27e0e4018a0efcd0f5
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40893
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

0 files changed, 0 insertions, 0 deletions