sysfs: add copyrights

Sysfs has gone through considerable amount of reimplementation.  Add
copyrights.  Any objections?  :-)

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index c05f961..d3be1e7 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -1,5 +1,13 @@
 /*
- * file.c - operations for regular (text) files.
+ * fs/sysfs/file.c - sysfs regular (text) file implementation
+ *
+ * Copyright (c) 2001-3 Patrick Mochel
+ * Copyright (c) 2007 SUSE Linux Products GmbH
+ * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
+ *
+ * This file is released under the GPLv2.
+ *
+ * Please see Documentation/filesystems/sysfs.txt for more information.
  */
 
 #include <linux/module.h>