libnvdimm, e820: fix numa node for e820-type-12 pmem ranges

Rather than punt on the numa node for these e820 ranges try to find a
better answer with memory_add_physaddr_to_nid() when it is available.

Cc: <stable@vger.kernel.org>
Reported-by: Boaz Harrosh <boaz@plexistor.com>
Tested-by: Boaz Harrosh <boaz@plexistor.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>