f2fs: add SPDX license identifiers

Remove the verbose license text from f2fs files and replace them with
SPDX tags.  This does not change the license of any of the code.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/xattr.h

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * fs/f2fs/xattr.h
  *
@@ -9,10 +10,6 @@
  * On-disk format of extended attributes for the ext2 filesystem.
  *
  * (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 #ifndef __F2FS_XATTR_H__
 #define __F2FS_XATTR_H__