sysfs: Initialised pci bus legacy_mem field before use

PPC64 is failing to boot the latest mmotm due to an uninitialised pointer in
pci_create_legacy_files(). The surprise is that machines boot at all and it
would appear to affect current mainline as well.  This patch fixes the problem.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/pci/pci-sysfs.c

@@ -655,8 +655,8 @@ void pci_create_legacy_files(struct pci_bus *b)
 		goto legacy_io_err;
 
 	/* Allocated above after the legacy_io struct */
-	sysfs_bin_attr_init(b->legacy_mem);
 	b->legacy_mem = b->legacy_io + 1;
+	sysfs_bin_attr_init(b->legacy_mem);
 	b->legacy_mem->attr.name = "legacy_mem";
 	b->legacy_mem->size = 1024*1024;
 	b->legacy_mem->attr.mode = S_IRUSR | S_IWUSR;