lib/edid_fill_fb: Support multiple framebuffers

Currently it's not possible to add multiple graphics driver into
one coreboot image. This patch series will fix this issue by providing
a single API that multiple graphics driver can use.

This is required for platforms that have two graphic cards, but
different graphic drivers, like Intel and Aspeed on server platforms or
Intel and Nvidia on consumer notebooks.

The goals are to remove duplicated fill_fb_framebuffer(), advertise of multiple
independent framebuffers in coreboot tables, and better runtime/build time
graphic configuration options.

Add an implementation in edid_fill_fb that supports registering
multiple framebuffers, each with its own configuration.

As the current code is only compiled for a single graphics driver
there's no change in functionality.

Change-Id: I7264c2ea2f72f36adfd26f26b00e3ce172133621
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
---
M src/include/edid.h
A src/include/framebuffer_info.h
M src/lib/edid_fill_fb.c
M src/mainboard/google/kukui/mainboard.c
4 files changed, 181 insertions(+), 60 deletions(-)