x86, olpc: Use pci subarch init for OLPC

Replace the #ifdef'ed OLPC-specific init functions by a conditional
x86_init function.  If the function returns 0 we leave pci_arch_init,
otherwise we continue.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Andres Salomon <dilinger@collabora.co.uk>
LKML-Reference: <43F901BD926A4E43B106BF17856F0755A318CE89@orsmsx508.amr.corp.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>