Run checkpatch on kernel-next, too.

TEST=Created a bad change in kernel-next and tried 'repo upload'.

Change-Id: I38201460aac94b4a16eb23c29647151e8e947bc3
diff --git a/pre-upload.py b/pre-upload.py
index 2034c12..d2b9d41 100644
--- a/pre-upload.py
+++ b/pre-upload.py
@@ -39,7 +39,8 @@
 def _setup_project_hooks():
   """Returns a dictionay of callbacks: dict[project] = [callback1, callback2]"""
   return {
-    "chromiumos/third_party/kernel": [_run_checkpatch]
+    "chromiumos/third_party/kernel": [_run_checkpatch],
+    "chromiumos/third_party/kernel-next": [_run_checkpatch],
     }
 
 def _run_project_hooks(project, hooks):