Replace SoC footprint (again). Make all vias the same size.

Replace SoC footprint (again). Make all vias the same size.

I've updated the SoC footprint to remove some silk and clean up the
corner pads to make them pass DRC.

This patch also switches all of the remaining vias to the small size;
no reason to have two drills for those.

Signed-off-by: Keith Packard <keithp@keithp.com>