we encountered 1MB flash so far, but we may encounter other
sizes on other machines when added to libreboot later on

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

Though not used in coreboot builds, and not injected into the
builds in any way, these files are now created seperately when
handling T480/T480s vendor files:

vendorfiles/t480/tb.bin
vendorfiles/t480s/tb.bin

These are created by extracting Lenovo's ThunderBolt firmware
from update files. The updated firmware fixes a bug; older firmware
enabled debug commands that wrote logs to the TB controller's
own flash IC, and it'd get full up with logs, bricking the controller.
If you've already been screwed by this, you must flash externally,
using a padded firmware from Lenovo's updates.

Lenovo's own updater requires creating a boot CD or booting
Windows. This patch in lbmk auto-downloads just the firmware,
and you can flash it externally.

You could simply do this as a matter of course, when installing
Libreboot. You are recommended to update the Lenovo UEFI/EC firmwares
first, before installing Libreboot; please look at the Libreboot
documentation to know exactly which versions.

Then dump the ThunderBolt firmware first, to be sure, and then you
can flash these files. Flashing these updates will prevent the bug
described here:

https://pcsupport.lenovo.com/us/en/products/laptops-and-netbooks/thinkpad-t-series-laptops/thinkpad-t480-type-20l5-20l6/20l5/solutions/ht508988

You can download Lenovo's installers for various ThinkPad models
there, including T480s/T480s. It is these downloads that this lbmk
patch uses, to extract those files directly.

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

Added t480s delta to deguard, for MFS config.

Updated coreboot/next to latest t480 patch set,
which includes t480s. This porting was done by
Mate Kukri.

also includes experimental t480s support

Also added a data.vbt file (not in the gerrit patch)
for the T480s.

I had to turn on 8254 legacy timer on t480s, otherwise
SeaBIOS would hang. Same issue I saw on OptiPlex 3050 Micro.

Minor issue:

On S3 resume, nvme0n1 for example got renamed to nvme0n2.
This caused a crash if running Linux from the nvme. I confirmed
this via live USB distro. So this port will need some tweaking
before it can be considered stable.

Also uses libgfxinit, which Mate recently fixed. I'm
going to enable libgfxinit on regular T480 next.

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