So we could set io apic routing when ACPI is not enabled.

[ Impact: prepare for new functionality ]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Len Brown <lenb@kernel.org>
LKML-Reference: <4A01C422.5070400@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>