libnvdimm, pfn: fix align attribute

Fix the format specifier so that the attribute can be parsed correctly.
Currently it returns decimal 1000 for a 4096-byte alignment.

Cc: <stable@vger.kernel.org>
Reported-by: Dave Jiang <dave.jiang@intel.com>
Fixes: 315c5625 ("libnvdimm, pfn: add 'align' attribute, default to HPAGE_SIZE")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/nvdimm/pfn_devs.c

@@ -108,7 +108,7 @@ static ssize_t align_show(struct device *dev,
 {
 	struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 
-	return sprintf(buf, "%lx\n", nd_pfn->align);
+	return sprintf(buf, "%ld\n", nd_pfn->align);
 }
 
 static ssize_t __align_store(struct nd_pfn *nd_pfn, const char *buf)