Add atv device repo to cm-12.1 default manifest

Change-Id: Ibf0ed2c27ee274851918b65206e0496eae2aa939
diff --git a/default.xml b/default.xml
index d63de13..58719e2 100644
--- a/default.xml
+++ b/default.xml
@@ -51,6 +51,7 @@
   <project path="device/generic/x86_64" name="device/generic/x86_64" groups="pdk" remote="aosp" />
   <project path="device/google/accessory/arduino" name="device/google/accessory/arduino" groups="device" remote="aosp" />
   <project path="device/google/accessory/demokit" name="device/google/accessory/demokit" groups="device" remote="aosp" />
+  <project path="device/google/atv" name="CyanogenMod/android_device_google_atv" groups="device" />
   <project path="device/qcom/sepolicy" name="CyanogenMod/android_device_qcom_sepolicy" />
   <project path="device/sample" name="device/sample" groups="pdk" remote="aosp" />
   <project path="docs/source.android.com" name="platform/docs/source.android.com" groups="pdk-cw-fs" remote="aosp" />