thermal: core: Use sysfs_emit_at() instead of scnprintf()

Follow the advice in Documentation/filesystems/sysfs.rst that show()
should only use sysfs_emit() or sysfs_emit_at() when formatting the
value to be returned to user space.
Signed-off-by: Nye xingchen <ye.xingchen@zte.com.cn>
[ rjw: Subject and changelog edits ]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/thermal/thermal_core.c

@@ -229,10 +229,9 @@ int thermal_build_list_of_policies(char *buf)
 	mutex_lock(&thermal_governor_lock);
 
 	list_for_each_entry(pos, &thermal_governor_list, governor_list) {
-		count += scnprintf(buf + count, PAGE_SIZE - count, "%s ",
-				   pos->name);
+		count += sysfs_emit_at(buf, count, "%s ", pos->name);
 	}
-	count += scnprintf(buf + count, PAGE_SIZE - count, "\n");
+	count += sysfs_emit_at(buf, count, "\n");
 
 	mutex_unlock(&thermal_governor_lock);