glacier: set has_trackball to true

Yes, it has a trackball.  Oops.

Change-Id: Ic6d13b409a830cd7d7032700c735d4949293702c
diff --git a/overlay/glacier/packages/apps/CMParts/res/values/config.xml b/overlay/glacier/packages/apps/CMParts/res/values/config.xml
index bbe40af..a446a98 100644
--- a/overlay/glacier/packages/apps/CMParts/res/values/config.xml
+++ b/overlay/glacier/packages/apps/CMParts/res/values/config.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <!-- Whether or not to display the trackball settings -->
-    <bool name="has_trackball">false</bool>
+    <bool name="has_trackball">true</bool>
     <bool name="has_rgb_notification_led">false</bool>
     <bool name="has_led_flash">true</bool>
 </resources>