PCI: OLPC: Only enable PCI configuration type override on XO-1

This configuration type override is for XO-1 only and must not happen
on XO-1.5.

Acked-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>