BROKEN/WIP: NEW MAINBOARD: Lenovo ThinkCentre M920 Tinym920qwip

WARNING!!!!! i915 driver crashes when loading (KMS driver).
Could not use GRUB or SeaBIOS; SeaBIOS hangs and USB input
fails in GRUB. U-Boot UEFI works, you can boot things.
If you want to set upp a headless service this machine is
totally fine, because you can just avoid loading i915 in
Linux, and just use the EFI framebuffer or the coreboot
framebuffer, or possibly boot xorg with nomodeset.

DO NOT MERGE! This machine needs a lot work work.

Initial notes:

This should cover both the M920q and M920x, though the
x variant is quite rare.

This is a mITX desktop system, documented here:
https://doc.coreboot.org/mainboard/lenovo/m920q.html

Thanks go to Maciej Pijanowski, who ported coreboot to
this board and submitted the code upstream. Libreboot is
using the version that was recently merged upstream in
the coreboot project.

It's not yet known how to auto-download the ME, because the
update images are incomplete. The only reliable way thus far
is to extract the factory dump. However, it's also uncertain
what modules to whitelist in me_cleaner, so for this board, we
only:

* Unlock all IFD regions, setting them read-write
* Set the HAP bit, which is functionally equivalent to
  a valid me_cleaner setup

The result will be a disabled ME, and read-write operation.
No binary images will be provided for now, in releases. You
must also create the directory:

dump/m920q/

Then just extract from the factory dump using:

./ifdtool --platform cnl -x libreboot.rom

Then just stick the files that it creates into there, and
the build should work. I've made lbmk automatically set the
HAP bit and unlock regions, when building with these.

Also, SeaBIOS hung so I restored the possibility of using
GRUB as primary, but GRUB USB input also didn't work! The
board's port author tested edk2 only, it seems. I don't really
want edk2 in lbmk just for this board.

So, I made U-Boot the only payload. It seems to work fine.
However, Debian Linux and OpenBSD both seemed to completely fail:
On OpenBSD it had errors pertaining to i915 video driver.

Debian Linux stalled at startup just when it's switching to
KMS, which would use the i915 driver.

Arch Linux installer, same thing: uses KMS, and failed.

The port author said edk2 was tested. edk2 provides a decent
GOP implementation, so maybe they were using an EFI framebuffer
when booting Linux.

Signed-off-by: Leah Rowe <leah@libreboot.org>

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