PCI: Remove pci_get_bus_and_slot() function

pci_get_bus_and_slot() is restrictive such that it assumes domain=0 as
where a PCI device is present. This restricts the device drivers to be
reused for other domain numbers.

Now that all users of pci_get_bus_and_slot() switched to
pci_get_domain_bus_and_slot(), it is now safe to remove this function.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>