[IA64] Altix pcibus_to_node implementation

The Altix subarch does not provide node information via ACPI. Instead hooks
are used to fixup pci structures. This patch determines the nodes for Altix
PCI busses.

Remote Bridges:
---------------
Altix supports remote I/O nodes without memory or processors but with bridges.
The TIOCA type of bridge is an AGP bridge and the PROM provides information
about the closest node. That information will be returned by pcibus_to_node.

The TIOCP remote bridge type is a PCI bridge but the PROM does not provide a
closest node id. pcibus_to_node will return -1 for devices on those bridges
meaning that device control structures may be allocated on any node.

Safeguard:
----------
Should the fixups result in invalid node information for a pci controller then
a warning will be printed and pcibus_to_node will return -1.


This patch also fixes the "FIXME" in sn_dma_alloc_coherent. This means that
dma_alloc_coherent will now use alloc_pages_node to allocate memory local to
the node that the PCI device is connected to.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>