PCI: Simplify pcie_bus_configure_settings() interface

Based on a patch by Jon Mason (see URL below).

All users of pcie_bus_configure_settings() pass arguments of the form
"bus, bus->self->pcie_mpss".  The "mpss" argument is redundant since we
can easily look it up internally.  In addition, all callers check
"bus->self" for NULL, which we can also do internally.

This patch simplifies the interface and the callers.  No functional change.

Reference: http://lkml.kernel.org/r/1317048850-30728-2-git-send-email-mason@myri.com
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 0fd1f15..57062b7 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -675,7 +675,7 @@
 /* these external functions are only available when PCI support is enabled */
 #ifdef CONFIG_PCI
 
-void pcie_bus_configure_settings(struct pci_bus *bus, u8 smpss);
+void pcie_bus_configure_settings(struct pci_bus *bus);
 
 enum pcie_bus_config_types {
 	PCIE_BUS_TUNE_OFF,