[IA64] show_mem() for IA64 sparsemem NUMA

On the ia64 architecture only this patch upgrades show_mem() for sparse
memory to be the same as it was for discontig memory.  It has been shown to
work on NUMA and flatmem architectures.

Signed-off-by: George Beshers <gbeshers@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>