9p: fix file headers

- add missing SPDX-License-Identifier
- remove (sometimes incorrect) file name from file header

Link: http://lkml.kernel.org/r/20211102134608.1588018-2-dominique.martinet@atmark-techno.com
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
diff --git a/net/9p/trans_common.h b/net/9p/trans_common.h
index c43babb..bab0833 100644
--- a/net/9p/trans_common.h
+++ b/net/9p/trans_common.h
@@ -1,15 +1,7 @@
+/* SPDX-License-Identifier: LGPL-2.1 */
 /*
  * Copyright IBM Corporation, 2010
  * Author Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of version 2.1 of the GNU Lesser General Public License
- * as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it would be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
- *
  */
 
 void p9_release_pages(struct page **, int);