We need to access it right way, so make sure that it is mapped already.

Prepare to put page table on local node, and nodemap is used before that.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
LKML-Reference: <4D1933C8.7060105@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>