AOD/LS - Large clock adjustments

For smaller displays and/or displays set to use a larger size/font,
the large clock would display too far down on the screen. Remove some
padding, and use variable sizes for the font depending on the
available height.

Fixes: 176474531
Test: manual, testing multiple display sizes and burn-in testing
Change-Id: I865ea965d83ae25ea9b53f6aacd37492ddc21930