microblaze/PCI: Add multidomain support for procfs

We create a procfs directory for every PCI bus.  Previously, the directory
name was just the bus number, so using the same bus number in different
domains caused a kernel crash when we tried to create a duplicate
directory.

Make pci_proc_domain() return the domain number, so procfs directories for
buses in domain 0 are named with just the bus number, and directories for
buses in other domains include both the domain number and the bus number.

[bhelgaas: changelog]
Signed-off-by: Bharat Kumar Gogada <bharatku@xilinx.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>

arch/microblaze/pci/pci-common.c

@@ -632,10 +632,10 @@ void pci_process_bridge_OF_ranges(struct pci_controller *hose,
 	}
 }
 
-/* Decide whether to display the domain number in /proc */
+/* Display the domain number in /proc */
 int pci_proc_domain(struct pci_bus *bus)
 {
-	return 0;
+	return pci_domain_nr(bus);
 }
 
 /* This header fixup will do the resource fixup for all devices as they are