implement early_io{re,un}map for ia64

commit cd7bcf32 upstream.

Needed for commit 2c992208

 ("intel-iommu: Detect DMAR in hyperspace at
probe time.) to build on IA64.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andy Whitcroft <apw@canonical.com>