[L] Change in coreboot[main]: acpi: Move acpigen_write_OSC_pci_domain to Xeon-SP

[Shuo Liu (Code Review)]

Attention is currently required from: Arthur Heymans, Christian Walter, Cliff Huang, Felix Held, Johnny Lin, Jonathan Zhang, Lance Zhao, Lean Sheng Tan, Nico Huber, Patrick Rudolph, Tim Chu, Tim Wawrzynczak.

Shuo Liu has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/81652?usp=email )

Change subject: acpi: Move acpigen_write_OSC_pci_domain to Xeon-SP
......................................................................

Patch Set 2:

(1 comment)

Patchset:

PS1:
> Revisited the comments from Nico and Felix, and checking through Linux kernel 5.19. […]

As to Point 1, below is a code segment of 
drivers/acpi/pci_root.c of Linux 5.19.rc8, with below characterstics,

1. one UUID for one PCI root, determined by its role
2. PCI control and CXL control will be handled by one _OSC call instead of 2 separate calls.

static acpi_status acpi_pci_run_osc(struct acpi_pci_root *root,
                                    const u32 *capbuf, u32 *pci_control,
                                    u32 *cxl_control)
{
        struct acpi_osc_context context = {
                .uuid_str = to_uuid(root),
                .rev = 1,
                .cap.length = cap_length(root),
                .cap.pointer = (void *)capbuf,
        };
        acpi_status status;

status = acpi_run_osc(root->device->handle, &context);
        if (ACPI_SUCCESS(status)) {
                *pci_control = acpi_osc_ctx_get_pci_control(&context);
                if (is_cxl(root))
                        *cxl_control = acpi_osc_ctx_get_cxl_control(&context);
                kfree(context.ret.pointer);
        }
        return status;
}