setup_IO_APIC_irqs could fail to get vector for some device when you have too
many devices, because at that time only boot cpu is online.  So check vector
for irq in setup_ioapic_dest and call setup_IO_APIC_irq to make sure IO-APIC
irq-routing table is initialized.

Also seperate setup_IO_APIC_irq from setup_IO_APIC_irqs.
Signed-off-by: Yinghai Lu <yinghai.lu@amd.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>