libnvdimm: Add DSM support for Address Range Scrub commands

Add support for the three ARS DSM commands:
- Query ARS Capabilities - Queries the firmware to check if a given
  range supports scrub, and if so, which type (persistent vs. volatile)
- Start ARS - Starts a scrub for a given range/type
- Query ARS Status - Checks status of a previously started scrub, and
  provides the error logs if any.

  The commands are described by the example DSM spec at:
  http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf

Also add these commands to the nfit_test test framework, and return
canned data.

Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

include/uapi/linux/ndctl.h

@@ -111,6 +111,11 @@ enum {
 	ND_CMD_VENDOR = 9,
 };
 
+enum {
+	ND_ARS_VOLATILE = 1,
+	ND_ARS_PERSISTENT = 2,
+};
+
 static inline const char *nvdimm_bus_cmd_name(unsigned cmd)
 {
 	static const char * const names[] = {
@@ -194,4 +199,9 @@ enum nd_driver_flags {
 enum {
 	ND_MIN_NAMESPACE_SIZE = 0x00400000,
 };
+
+enum ars_masks {
+	ARS_STATUS_MASK = 0x0000FFFF,
+	ARS_EXT_STATUS_SHIFT = 16,
+};
 #endif /* __NDCTL_H__ */