PCI: Move PRESERVE_BOOT_CONFIG _DSM evaluation to pci_register_host_bridge()

PCI: Move PRESERVE_BOOT_CONFIG _DSM evaluation to pci_register_host_bridge()

Move the PRESERVE_BOOT_CONFIG _DSM evaluation from acpi_pci_root_create()
to pci_register_host_bridge().

This will help unify the ACPI _DSM path and the DT-based
"linux,pci-probe-only" paths.

This should be safe because it happens earlier than it used to:

    acpi_pci_root_create
      pci_create_root_bus
        pci_register_host_bridge
  +       bridge->preserve_config = pci_preserve_config(bridge)
            pci_acpi_preserve_config
  +           acpi_evaluate_dsm_typed(DSM_PCI_PRESERVE_BOOT_CONFIG)
  -   acpi_evaluate_dsm_typed(DSM_PCI_PRESERVE_BOOT_CONFIG)

No functional change intended.

Link: https://lore.kernel.org/r/20240508174138.3630283-2-vidyas@nvidia.com
Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>