defconfigs: mogami/zeus: Give all the space to /system

* 450MB is not and will not be enough for lollipop
* /data gets full on ART even with very few apps
* Give the whole space to system, user is going to need a second partition
  on the SD card that will be mounted as /data

Change-Id: I967e612c46ec52cb2b5561edfaa7f4c5a7abf892