VGA doesn't work on coreboot linear framebuffer

[cl91]

We need to figure out how to get console working on coreboot bios (especially with libgfxinit high-resolution linear framebuffer).

• [ ] Enable serial console in coreboot config and reflash the Thinkpad X60 bios so we can get debugging log on serial port.
• [ ] Figure out where the coreboot linear framebuffer is and blit bitmap fonts there.