libnvdimm: support for legacy (non-aliasing) nvdimms

The libnvdimm region driver is an intermediary driver that translates
non-volatile "region"s into "namespace" sub-devices that are surfaced by
persistent memory block-device drivers (PMEM and BLK).

ACPI 6 introduces the concept that a given nvdimm may simultaneously
offer multiple access modes to its media through direct PMEM load/store
access, or windowed BLK mode.  Existing nvdimms mostly implement a PMEM
interface, some offer a BLK-like mode, but never both as ACPI 6 defines.
If an nvdimm is single interfaced, then there is no need for dimm
metadata labels.  For these devices we can take the region boundaries
directly to create a child namespace device (nd_namespace_io).

Acked-by: Christoph Hellwig <hch@lst.de>
Tested-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/nvdimm/Makefile b/drivers/nvdimm/Makefile
index 88afd0d..af5e276 100644
--- a/drivers/nvdimm/Makefile
+++ b/drivers/nvdimm/Makefile
@@ -5,3 +5,5 @@
 libnvdimm-y += dimm_devs.o
 libnvdimm-y += dimm.o
 libnvdimm-y += region_devs.o
+libnvdimm-y += region.o
+libnvdimm-y += namespace_devs.o