I'm going to add the ability to process multiple .dtsi files since this will be required for this work.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/da9406c62dd1cee6b95de3e0fd8d9dbae8df9251

commit da9406c62dd1cee6b95de3e0fd8d9dbae8df9251
Author: Simon Glass <sjg@chromium.org>
Date: Thu Sep 28 06:52:10 2017

cros-unibuild: Support splitting .dtsi files

For projects where there are a large number of partners all wanting to add
configuration at once, having all the config in one file invites merge
conflicts and inadvertent edits.

Add support for spliting the config into a separate file for each model,
for example

   astronaut.dtsi
   robo.dtsi
   santa.dtsi

To use this, call install_private_model_files from the private
chromeos-config-bsp ebuild (which installs all files) instead of
install_private_model_file (which only installs a file called model.dtsi).

BUG= chromium:764755 
TEST=Manually tested with a modified configuration
$ emerge-reef-uni chromeos-firmware-reef

Change-Id: I6f9b59ba5b858968184464739ba2fd8b46aaaa0d
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/677091
Reviewed-by: Jason Clinton <jclinton@chromium.org>

[modify] https://crrev.com/da9406c62dd1cee6b95de3e0fd8d9dbae8df9251/eclass/cros-unibuild.eclass

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/ce23a8dac8a4e6c0dcf483067b55ff1ba9557e5a

commit ce23a8dac8a4e6c0dcf483067b55ff1ba9557e5a
Author: Simon Glass <sjg@chromium.org>
Date: Mon Oct 23 01:34:47 2017

cros-unibuild: Support installing non-private model files

Add support for installing model files from a public overlay. The only
difference is that we don't need to add the 'private-' prefix.

BUG= chromium:764755 
TEST=none yet

Change-Id: I9059e558a140a49d54c5dc65c724b9ec5d8bcf47
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/727031
Reviewed-by: Jason Clinton <jclinton@chromium.org>

[modify] https://crrev.com/ce23a8dac8a4e6c0dcf483067b55ff1ba9557e5a/eclass/cros-unibuild.eclass

This is fixed so far as the unibuild architecture and impl is concerned.