ACPI: call init_acpi_device_notify() explicitly rather than as initcall

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>