PCI: Move resource reassignment func declarations into pci/pci.h

PCI: Move resource reassignment func declarations into pci/pci.h

Neither pci_reassign_bridge_resources() nor pci_reassign_resource() is used
outside of the PCI subsystem. They seem to be naturally static functions
but since resource fitting/assignment is split between setup-bus.c and
setup-res.c, they fall into different sides of the divide and need to be
declared.

Move the declarations of pci_reassign_bridge_resources() and
pci_reassign_resource() into pci/pci.h to keep them internal to PCI
subsystem.

Link: https://lore.kernel.org/r/20250311174701.3586-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>