PCI: Remove unused pci_configure_slot()

All pci_configure_slot() uses have been removed, so remove the definition
as well.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>

diff --cc drivers/pci/probe.c
Simple merge

diff --cc include/linux/pci_hotplug.h
Simple merge