PCI Hotplug: fakephp: add duplicate slot name debugging

The PCI core now manages slot names on behalf of slot detection
and slot hotplug drivers, including the handling of duplicate
slot names.

We can use the fakephp driver to help test the new functionality.
Add a 'dup_slots' module param to force fakephp to create multiple
slots with the same name. We can then verify that the PCI core
correctly renamed the slots.

	sapphire:/sys/bus/pci/slots # modprobe fakephp dup_slots
	sapphire:/sys/bus/pci/slots # ls
	fake    fake-10  fake-3  fake-5  fake-7  fake-9
	fake-1  fake-2   fake-4  fake-6  fake-8

Cc: kristen.c.accardi@intel.com
Cc: matthew@wil.cx
Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>