FAFT: Fix flashrom utility script to use proper args

The image argument used to be ignored when enabling WP regions.
With the later flashrom update, this argument is now validated and
the command fails.

BUG=b:175614843
TEST=Ran firmware_WriteProtectFunc FAFT test

Change-Id: I08bf55f7645712d36336f9745fc2cb66e0b7bec5
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/2605628
Tested-by: Dossym Nurmukhanov <dossym@chromium.org>
Reviewed-by: Philip Chen <philipchen@chromium.org>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Commit-Queue: Dossym Nurmukhanov <dossym@chromium.org>
diff --git a/client/cros/faft/utils/saft_flashrom_util.py b/client/cros/faft/utils/saft_flashrom_util.py
index 0475b54..8570bff 100644
--- a/client/cros/faft/utils/saft_flashrom_util.py
+++ b/client/cros/faft/utils/saft_flashrom_util.py
@@ -317,8 +317,8 @@
         @param region: Region to set (usually WP_RO)
         @param enabled: if True, run --wp-enable; if False, run --wp-disable.
         """
-        cmd = 'flashrom %s --verbose --image %s --wp-region %s' % (
-                self._target_command, image_file, region)
+        cmd = 'flashrom %s --verbose --image %s:%s --wp-region %s' % (
+                self._target_command, region, image_file, region)
         if enabled is not None:
             cmd += ' '
             cmd += '--wp-enable' if enabled else '--wp-disable'