[Open-graphics] Jumper count to disconnect DDC from DVI connector

[mykrowatt at comcast.net]

   To answer an earlier question: if we want to include a feature on OGC1 to disconnect the DDC signals from the DVI connector so that the external tool will have control of those signals, only two lines need to be disconnected: SCL and SDA.  So the cost impact of doing it with jumper plugs would be minimal.
   It would also be possible to ship a cost-minimized board, with the header to be installed in the field and default tracks to be cut.  Home hobbyist tools are adequate to retrofit the board to accept external tools, as long as the artwork includes provision for the field rework.