Resize InCallUI for small devices.

In the InCallUI for devices smaller than nexus 4, the dialpad digits are
squished because the text in the call card is too big. Shrink the text
selectively for smaller devices (by moving the current default sizes to
the >600dp height devices). See
http://developer.android.com/guide/topics/resources/providing-resources.html#BestMatch
for reference.

Bug:18122087
Change-Id: I3eceae520d5039dd18c39434eb548288d8ce4e61