kboot: Add SMBIOS information for U-Boot

[kettenis]

No description provided.

[kettenis]

U-Boot recently fixed the issue with advertising SMBIOS tables at addresses above 4G that forced me to disable SMBIOS support. Now that it is fixed, let's provide some meaningful information to fill the tables. We could add this directly to the device tree but:

1. Doing so would be more work
2. Would introduce DT schema validation errors since the bindings for this are in the Linux tree (yet)

Personally I don't particularly care about SMBIOS support, but there are Linux tools that expect it to be present. IIRC this does include some bug reporting tools used by Fedora.

[chadmed]

I'm not sure if this is a particularly good solution to the problem as we're not really doing anything about the root cause. If certain tools do not support retrieving platform information from the DT, then they are broken on a nontrivial number of computers. Those tools should be fixed, and we shouldn't kludge our way around that brokenness.

Furthermore, having info split across the DT and U-Boot's SMBIOS will subtly break other tools which expect to be parsing information from one or the other, even if it fixes ones that are OF-unaware. For example, this would make KDE Info Centre display less information than it does now, as it will not try and parse the DT if it finds SMBIOS tables first. We're just shifting the problem someplace else by doing this.

[Conan-Kudo]

On the other hand, is there a reason we can't make the SMBIOS data more complete? Generally speaking, OF data isn't stable in the same way that SMBIOS data is, and way more tools know how to read SMBIOS than OF data.