[POWERPC] Use global_number in ppc32 pci_controller

Make the pci_controller struct use global_number for the PHB domain number
instead of index to match what ppc64 does and reuse its pci_domain_nr code.

Introduced a pci-common.c to handle shared code between ppc32 & ppc64.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/kernel/pci-common.c

@@ -0,0 +1,53 @@
+/*
+ * Contains common pci routines for ALL ppc platform
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/mm.h>
+#include <linux/list.h>
+#include <linux/syscalls.h>
+#include <linux/irq.h>
+#include <linux/vmalloc.h>
+
+#include <asm/processor.h>
+#include <asm/io.h>
+#include <asm/prom.h>
+#include <asm/pci-bridge.h>
+#include <asm/byteorder.h>
+#include <asm/machdep.h>
+#include <asm/ppc-pci.h>
+#include <asm/firmware.h>
+
+#ifdef DEBUG
+#include <asm/udbg.h>
+#define DBG(fmt...) printk(fmt)
+#else
+#define DBG(fmt...)
+#endif
+
+/*
+ * Return the domain number for this bus.
+ */
+int pci_domain_nr(struct pci_bus *bus)
+{
+	if (firmware_has_feature(FW_FEATURE_ISERIES))
+		return 0;
+	else {
+		struct pci_controller *hose = pci_bus_to_host(bus);
+
+		return hose->global_number;
+	}
+}
+
+EXPORT_SYMBOL(pci_domain_nr);