sockit: tidy up comment
sockit: Enable vga_lcd core

Pixel clock is currently hard coded to 25.2 MHz, which is
640x480@60.
It's not very usable yet, since the avalon bus accesses are not
bursted, so constant buffer underruns occurs, but while running test
software about 1/10 of a screen is correctly showing, so
everything else seems correctly hooked up.