PCI: Convert pcibios_resource_to_bus() to take a pci_bus, not a pci_dev

PCI: Convert pcibios_resource_to_bus() to take a pci_bus, not a pci_dev

commit fc2798502f860b18f3c7121e4dc659d3d9d28d74 upstream.

These interfaces:

  pcibios_resource_to_bus(struct pci_dev *dev, *bus_region, *resource)
  pcibios_bus_to_resource(struct pci_dev *dev, *resource, *bus_region)

took a pci_dev, but they really depend only on the pci_bus.  And we want to
use them in resource allocation paths where we have the bus but not a
device, so this patch converts them to take the pci_bus instead of the
pci_dev:

  pcibios_resource_to_bus(struct pci_bus *bus, *bus_region, *resource)
  pcibios_bus_to_resource(struct pci_bus *bus, *resource, *bus_region)

In fact, with standard PCI-PCI bridges, they only depend on the host
bridge, because that's the only place address translation occurs, but
we aren't going that far yet.

[bhelgaas: changelog]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Dirk Behme <dirk.behme@gmail.com>
[lizf: Backported to 3.4:
 - make changes to pci_host_bridge() instead of find_pci_root_bus()
 - adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>