ia64 / sba_iommu: Use NUMA_NO_NODE, not MAX_NUMNODES, for unknown node

MAX_NUMNODES is typically used for sizing arrays.  NUMA_NO_NODE is the
usual value for "we don't know what node this is on," e.g., it is the
error return from acpi_get_node().

This changes the ioc->node value for unknown nodes from MAX_NUMNODES to
NUMA_NO_NODE.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>