i3100: Enable second IOAPIC for PCI-X

i3100/i5000 have a second IOAPIC which handles IRQs for PCI-X.
Add code to enable it.

Change-Id: Ib447628f501b152c8adc9c7c89bd09b5615b9e5a
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Reviewed-on: http://review.coreboot.org/1118
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
2 files changed