[IA64] hotplug/ia64: SN Hotplug Driver - pci_find_next_bus export

The pci_find_next_bus function is listed as being exported to drivers.  It is
not EXPORT_SYMBOL'd.

Signed-off-by: Prarit Bhargava <prarit@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>