Remove old device list

The device list hasn't aged well. All these devices are over a decade old. umass
supports thunb drives almost universally, and the list is too long to try to
list here.

Remove some obsolete advice as well. This isn't the place to talk about how to
create FAT filesystems, nor now to mount them. The only advice that's still
useful is the rescanning of a multi-slot flash adapater.

MFC After: 3 days