powerpc/PCI: factor out pcibios_setup()

The PCI core provides a generic pcibios_setup() routine.  Drop this
architecture-specific version in favor of that.
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NMyron Stowe <myron.stowe@redhat.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

arch/powerpc/kernel/pci-common.c

@@ -200,11 +200,6 @@ int pcibios_add_platform_entries(struct pci_dev *pdev)
 	return device_create_file(&pdev->dev, &dev_attr_devspec);
 }
 
-char __devinit *pcibios_setup(char *str)
-{
-	return str;
-}
-
 /*
  * Reads the interrupt pin to determine if interrupt is use by card.
  * If the interrupt is used, then gets the interrupt line from the