Heli: add the servo overlay for heli

Heli is a rambi clone and references the rambi overlay.

BUG=chrome-os-partner:41289
TEST=run 'cros_workon --host start hdctools'
         'sudo emerge hdctools'
         'sudo servod --board heli'

Change-Id: I5d34b5e5571d74388e1dcace2ff8b973cfb6e476
Signed-off-by: Kaiyen Chang <kaiyen.chang@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/277384
Reviewed-by: Mohammed Habibulla <moch@google.com>
(cherry picked from commit 562cc3b8be33113b4b7e7fb4a70495b671734b4f)
Reviewed-on: https://chromium-review.googlesource.com/287284
Reviewed-by: Mohammed Habibulla <moch@chromium.org>
Tested-by: Marc Jones <marc.jones@se-eng.com>
Commit-Queue: Marc Jones <marc.jones@se-eng.com>
diff --git a/servo/data/servo_heli_overlay.xml b/servo/data/servo_heli_overlay.xml
new file mode 100644
index 0000000..134e5ad
--- /dev/null
+++ b/servo/data/servo_heli_overlay.xml
@@ -0,0 +1,5 @@
+<root>
+  <include>
+    <name>servo_rambi_overlay.xml</name>
+  </include>
+</root>