In some rare cases it seems that make tries to build $(objgenerated)/assembly.inc before the build-dirs target has finished, and so assembly.inc can't be written. Enforce that build-dirs is done before assembly.inc starts. BUG=chromium:1098215 BRANCH=none TEST=none Change-Id: Ib141ea45a43836cfdde0059523c331fe5286b06d Signed-off-by: Patrick Georgi <pgeorgi@google.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/42883 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Aaron Durbin <adurbin@chromium.org>