libnvdimm, nfit: enable support for volatile ranges

Allow volatile nfit ranges to participate in all the same infrastructure
provided for persistent memory regions. A resulting resulting namespace
device will still be called "pmem", but the parent region type will be
"nd_volatile". This is in preparation for disabling the dax ->flush()
operation in the pmem driver when it is hosted on a volatile range.

Cc: Jan Kara <jack@suse.cz>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index a6c4036..5929eb6 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -331,7 +331,7 @@ struct device *nd_pfn_create(struct nd_region *nd_region)
 	struct nd_pfn *nd_pfn;
 	struct device *dev;
 
-	if (!is_nd_pmem(&nd_region->dev))
+	if (!is_memory(&nd_region->dev))
 		return NULL;
 
 	nd_pfn = nd_pfn_alloc(nd_region);
@@ -354,7 +354,7 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
 	if (!pfn_sb || !ndns)
 		return -ENODEV;
 
-	if (!is_nd_pmem(nd_pfn->dev.parent))
+	if (!is_memory(nd_pfn->dev.parent))
 		return -ENODEV;
 
 	if (nvdimm_read_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb), 0))