Delete config.dtb support

With Fizz/Coral migrations complete, this deletes legacy support for
device-tree based cros_config impls.

BUG=b:119104647
TEST=cros tryjob coral-release-trybot
CQ-DEPEND=CL:*709755, CL:*709786

Change-Id: I8b0b347a9e6b9a8fb4397945d558de1c0fc9aea9
Reviewed-on: https://chromium-review.googlesource.com/1319952
Commit-Ready: C Shapiro <shapiroc@chromium.org>
Tested-by: C Shapiro <shapiroc@chromium.org>
Reviewed-by: Alex Klein <saklein@chromium.org>
diff --git a/build_library/base_image_util.sh b/build_library/base_image_util.sh
index f61677c..ce947d6 100755
--- a/build_library/base_image_util.sh
+++ b/build_library/base_image_util.sh
@@ -2,7 +2,6 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-CHROMEOS_MASTER_CONFIG_FILE="${BOARD_ROOT}/usr/share/chromeos-config/config.dtb"
 CHROMEOS_MASTER_JSON_CONFIG_FILE="${BOARD_ROOT}/usr/share/chromeos-config/config.json"
 
 check_full_disk() {
@@ -292,10 +291,6 @@
     models=$(grep '"name":' "${CHROMEOS_MASTER_JSON_CONFIG_FILE}" \
       | uniq | sed -e 's/.*"name": "\(.*\)".*/\1/' | tr '\n' ' ')
     [[ -n "${models}" ]] && model_flags+=( --models "${models%% }" )
-  elif [[ -f "${CHROMEOS_MASTER_CONFIG_FILE}" ]]; then
-    models=$(fdtget "${CHROMEOS_MASTER_CONFIG_FILE}" -l /chromeos/models \
-      | tr '\n' ' ')
-    [[ -n "${models}" ]] && model_flags+=( --models "${models%% }" )
   fi
 
   "${CHROMITE_BIN}/cros_set_lsb_release" \