Fix interaction between nosmp and pcibios_fixup_irqs().

When we boot with nosmp we dont have all the mptable info, so
IO_APIC_get_PCI_irq_vector() doesnt work and devices just end up getting a
wrong interrupt.

From: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>