ACPI: call init_acpi_device_notify() explicitly rather than as initcall

This patch makes acpi_init() call init_acpi_device_notify() directly.
Previously, init_acpi_device_notify() was an arch_initcall (sequence 3),
so it was called before acpi_init() (a subsys_initcall at sequence 4).

init_acpi_device_notify() sets the platform_notify and
platform_notify_remove function pointers.  These pointers
are not used until acpi_init() enumerates ACPI devices in
this path:

    acpi_init()
	    acpi_scan_init()
		acpi_bus_scan()
		    acpi_add_single_object()
			acpi_device_register()
			    device_add()
				<use platform_notify>

So it is sufficient to have acpi_init() call init_acpi_device_notify()
directly before it enumerates devices.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/bus.c

@@ -855,6 +855,7 @@ static int __init acpi_init(void)
 		acpi_kobj = NULL;
 	}
 
+	init_acpi_device_notify();
 	result = acpi_bus_init();
 
 	if (!result) {

drivers/acpi/glue.c

@@ -286,10 +286,8 @@ static int acpi_platform_notify_remove(struct device *dev)
 	return 0;
 }
 
-static int __init init_acpi_device_notify(void)
+int __init init_acpi_device_notify(void)
 {
-	if (acpi_disabled)
-		return 0;
 	if (platform_notify || platform_notify_remove) {
 		printk(KERN_ERR PREFIX "Can't use platform_notify\n");
 		return 0;
@@ -298,5 +296,3 @@ static int __init init_acpi_device_notify(void)
 	platform_notify_remove = acpi_platform_notify_remove;
 	return 0;
 }
-
-arch_initcall(init_acpi_device_notify);

drivers/acpi/internal.h

 /* For use by Linux/ACPI infrastructure, not drivers */
 
+int init_acpi_device_notify(void);
 int acpi_scan_init(void);
 int acpi_system_init(void);