servod: Fix init function to properly init ftdi dummy spots.

BUG=chromium:629550
TEST=Can init servod with a servo v2.

Change-Id: Ie572729cfc801d157471f353b92e983f016b7821
Reviewed-on: https://chromium-review.googlesource.com/361575
Commit-Ready: Kevin Cheng <kevcheng@chromium.org>
Tested-by: Kevin Cheng <kevcheng@chromium.org>
Tested-by: Todd Broch <tbroch@chromium.org>
Reviewed-by: Todd Broch <tbroch@chromium.org>
diff --git a/servo/servo_interfaces.py b/servo/servo_interfaces.py
index a51e520..4496a0b 100644
--- a/servo/servo_interfaces.py
+++ b/servo/servo_interfaces.py
@@ -27,8 +27,8 @@
 SERVO_V2_DEFAULTS = [(0x18d1, 0x5002)]
 for vid, pid in SERVO_V2_DEFAULTS:
   INTERFACE_DEFAULTS[vid][pid] = \
-    ['dummy', 'ftdi_i2c', 'ftdi_uart', 'ftdi_uart', 'dummy',
-     'dummy', 'ftdi_uart', 'ftdi_uart',
+    ['ftdi_dummy', 'ftdi_i2c', 'ftdi_uart', 'ftdi_uart', 'ftdi_dummy',
+     'ftdi_dummy', 'ftdi_uart', 'ftdi_uart',
      {'name': 'ec3po_uart'},
      {'name': 'ec3po_uart'}]