Add .gitupstream file

Change-Id: I4a8731d7c118e9b711a655e417018b6ce32b70b8
diff --git a/.gitupstream b/.gitupstream
new file mode 100644
index 0000000..96e9a7d
--- /dev/null
+++ b/.gitupstream
@@ -0,0 +1 @@
+https://git.codelinaro.org/clo/la/platform/external/json-c