PCI: of_property: Add support for NULL pdev in of_pci_set_address()

PCI: of_property: Add support for NULL pdev in of_pci_set_address()

The pdev (pointer to a struct pci_dev) parameter of of_pci_set_address()
cannot be NULL.

In order to use of_pci_set_address() when creating the PCI root bus node,
it needs to support a NULL pdev parameter. Indeed, in the case of the PCI
root bus node creation, no pdev is available and of_pci_set_address() will
be used with the bridge windows.

Allow to call of_pci_set_address() with a NULL pdev.

Link: https://lore.kernel.org/r/20250224141356.36325-4-herve.codina@bootlin.com
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>