[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>
diff --git a/arch/powerpc/kernel/pci_32.c b/arch/powerpc/kernel/pci_32.c
index 2d4a1c4..56deb31 100644
--- a/arch/powerpc/kernel/pci_32.c
+++ b/arch/powerpc/kernel/pci_32.c
@@ -620,7 +620,7 @@
 	*hose_tail = hose;
 	hose_tail = &hose->next;
 
-	hose->index = next_controller_index++;
+	hose->global_number = next_controller_index++;
 
 	return hose;
 }
@@ -1336,7 +1336,7 @@
 		if (!res->flags) {
 			if (io_offset)
 				printk(KERN_ERR "I/O resource not set for host"
-				       " bridge %d\n", hose->index);
+				       " bridge %d\n", hose->global_number);
 			res->start = 0;
 			res->end = IO_SPACE_LIMIT;
 			res->flags = IORESOURCE_IO;
@@ -1350,7 +1350,7 @@
 				if (i > 0)
 					continue;
 				printk(KERN_ERR "Memory resource not set for "
-				       "host bridge %d\n", hose->index);
+				       "host bridge %d\n", hose->global_number);
 				res->start = hose->pci_mem_offset;
 				res->end = ~0U;
 				res->flags = IORESOURCE_MEM;