pushimage: Add hps_firmware as valid sign_type

This CL added hps_firmware signing:
https://chromium-review.googlesource.com/c/chromiumos/chromite/+/3388260
But did not add support for hps_firmware as a sign_type.

BUG=b:219371209
TEST=config/refresh_generated_files

Change-Id: I384b084b9b8be05c30d4f19ba3d77ae821f4cde9
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/3459340
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: Evan Benn <evanbenn@chromium.org>
Auto-Submit: Evan Benn <evanbenn@chromium.org>
Commit-Queue: Evan Benn <evanbenn@chromium.org>
diff --git a/api/controller/image_unittest.py b/api/controller/image_unittest.py
index b4a440c..ceff870 100644
--- a/api/controller/image_unittest.py
+++ b/api/controller/image_unittest.py
@@ -375,7 +375,7 @@
         common_pb2.IMAGE_TYPE_RECOVERY, common_pb2.IMAGE_TYPE_FACTORY,
         common_pb2.IMAGE_TYPE_FIRMWARE, common_pb2.IMAGE_TYPE_ACCESSORY_USBPD,
         common_pb2.IMAGE_TYPE_ACCESSORY_RWSIG, common_pb2.IMAGE_TYPE_BASE,
-        common_pb2.IMAGE_TYPE_GSC_FIRMWARE
+        common_pb2.IMAGE_TYPE_GSC_FIRMWARE, common_pb2.IMAGE_TYPE_HPS_FIRMWARE,
     ])
     rc = image_controller.PushImage(req, self.NewResponse(),
                                     self.validate_only_config)