[PATCH] ia64: bail out of sba_init() if no hardware found

This patch against 2.5 gets rid of the following annoying but
harmless messages when booting a generic kernel on a non-ZX1 box:

        No IOC for PCI Bus 0000:00 in ACPI
        No IOC for PCI Bus 0000:01 in ACPI
        ...

We just forgot to bail out of the SBA IOMMU init function if it didn't
find any SBA hardware.

arch/ia64/hp/common/sba_iommu.c

@@ -1849,10 +1849,12 @@ static struct file_operations ioc_map_fops = {
 static void __init
 ioc_proc_init(void)
 {
-	if (ioc_list) {
 	struct proc_dir_entry *dir, *entry;
 
 	dir = proc_mkdir("bus/mckinley", 0);
+	if (!dir)
+		return;
+
 	entry = create_proc_entry(ioc_list->name, 0, dir);
 	if (entry)
 		entry->proc_fops = &ioc_fops;
@@ -1860,7 +1862,6 @@ ioc_proc_init(void)
 	entry = create_proc_entry("bitmap", 0, dir);
 	if (entry)
 		entry->proc_fops = &ioc_map_fops;
-	}
 }
 #endif
 
@@ -1946,6 +1947,8 @@ static int __init
 sba_init(void)
 {
 	acpi_bus_register_driver(&acpi_sba_ioc_driver);
+	if (!ioc_list)
+		return 0;
 
 #ifdef CONFIG_PCI
 	{