[PATCH] add x86-64 Kconfig options for sparsemem

Add the requisite arch specific Kconfig options to enable the use of the
sparsemem implementation for NUMA kernels on x86-64.

Signed-off-by: Matt Tolentino <matthew.e.tolentino@intel.com>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>