OMAP: Add DDC i2c_bus_num to board files

Add i2c bus number for DVI output for boards with DVI output where the
i2c bus has been confirmed to be connected and working. The driver uses
this to detect if a panel is connected and to read EDID.

Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>