puff: initial servod overlay

BUG=b:140912856
BRANCH=none
TEST=servod --board=puff

Change-Id: I28ecdaaf98d4784d2d39f078607abc067212e9b6
Signed-off-by: Kangheui Won <khwon@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/hdctools/+/1860183
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-by: Shelley Chen <shchen@chromium.org>
Reviewed-by: Aseda Aboagye <aaboagye@chromium.org>
Commit-Queue: Edward O'Callaghan <quasisec@chromium.org>
diff --git a/servo/servo_interfaces.py b/servo/servo_interfaces.py
index ab9fdaf..d14a5dd 100644
--- a/servo/servo_interfaces.py
+++ b/servo/servo_interfaces.py
@@ -298,6 +298,7 @@
     'octopus_npcx',
     'pbody',
     'poppy',
+    'puff',
     'rammus',
     'reef',
     'sarien',