pmem, memremap: convert to numa aware allocations

Given that pmem ranges come with numa-locality hints, arrange for the
resulting driver objects to be obtained from node-local memory.

Reviewed-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>