cros_bundle_firmware: don't add u-boot.dtb to CBFS

It's unused.

BUG=chromium:595715
BRANCH=none
TEST=none

Change-Id: If83ea687fda2c276cd802da052de18cba54dce74
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://chromium-review.googlesource.com/414345
Commit-Ready: Patrick Georgi <pgeorgi@chromium.org>
Tested-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-by: Stefan Reinauer <reinauer@chromium.org>
1 file changed