PCI: pull pcibios_setup() up into core

Currently, all of the architectures implement their own pcibios_setup()
routine.  Most of the implementations do nothing so this patch introduces
a generic (__weak) routine in the core that can be used by all
architectures as a default.  If necessary, it can be overridden by
architecture-specific code.

Signed-off-by: Myron Stowe <myron.stowe@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/include/linux/pci.h b/include/linux/pci.h
index d8c379d..f91143e 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -642,6 +642,7 @@
 
 void pcibios_fixup_bus(struct pci_bus *);
 int __must_check pcibios_enable_device(struct pci_dev *, int mask);
+/* Architecture specific versions may override this (weak) */
 char *pcibios_setup(char *str);
 
 /* Used only when drivers/pci/setup.c is used */