Use builtin bpfmt preupload check

Test: try and upload a commit with a badly formatted *.bp file
Change-Id: I784ce332c51c0450066e0a90e8201e4a56375666
diff --git a/PREUPLOAD.cfg b/PREUPLOAD.cfg
index 7ebbce9..304c3c1 100644
--- a/PREUPLOAD.cfg
+++ b/PREUPLOAD.cfg
@@ -1,12 +1,9 @@
 [Hook Scripts]
 check_generated_tests_up_to_date = tools/test_presubmit.py
 
-# Ensure that bp files are correctly formatted.
-# Note: uses libcore's script.
-bpfmt-check = ${REPO_ROOT}/libcore/tools/check-bpfmt.sh ${PREUPLOAD_COMMIT}
-
 [Builtin Hooks]
 cpplint = true
+bpfmt = true
 
 [Builtin Hooks Options]
 # Cpplint prints nothing unless there were errors.