[IA64] iommu: Add a dummy iommu_table.h file in IA64.

We don't need a comlex IOMMU dependency list on IA64 so
we just define the IOMMU_* macro as a dummy.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>