mtx: link VIDEO in the right place
mtx: move things about to allow space for unpack

Otherwise we fall over ourselves
mtx: correct VDP

Ports 1 and 2 not 0 and 1
mtx: Initialize the VDP and use it for vt work

Currently this is only half working - we init the vdp but have no font. We
need to upload our own font as CP/M or other boot code might not be using
the VDP display.