kbuild: Add copyright to modpost.c

It seems popular to protect your work with copyright, so I decided to do
so for modpost which I patch a great deal atm.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 7f25354..de0a9ee 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -2,7 +2,7 @@
  *
  * Copyright 2003       Kai Germaschewski
  * Copyright 2002-2004  Rusty Russell, IBM Corporation
- *
+ * Copyright 2006       Sam Ravnborg
  * Based in part on module-init-tools/depmod.c,file2alias
  *
  * This software may be used and distributed according to the terms