add opensource tarballs to repo

for now, just dump the tarballs in a repo. Eventually we may move
each of these packages to separate repos.

Change-Id: I0d6837335185fed4c2029f19eedd68a897e12f97
diff --git a/default.xml b/default.xml
index 05189b6..b808a81 100644
--- a/default.xml
+++ b/default.xml
@@ -19,6 +19,7 @@
   <project name="vendor-broadcom-magnum"        path="vendor/broadcom/magnum"/>
   <project name="vendor-broadcom-nexus"         path="vendor/broadcom/nexus"/>
   <project name="vendor-broadcom-rockford"      path="vendor/broadcom/rockford"/>
+  <project name="vendor-opensource-tarballs"    path="vendor/opensource/tarballs"/>
 
 <!--
   <project name="rootfs"                        path="rootfs"/>