udf: kill useless file header comments for vfs method implementations

There's not need to document vfs method invocation rules, we have
Documentation/filesystems/vfs.txt and Documentation/filesystems/Locking
for that.  Also a lot of these comments where either plain wrong or
horrible out of date.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/udf/dir.c

@@ -188,32 +188,6 @@ static int do_udf_readdir(struct inode *dir, struct file *filp,
 	return 0;
 }
 
-/*
- * udf_readdir
- *
- * PURPOSE
- *	Read a directory entry.
- *
- * DESCRIPTION
- *	Optional - sys_getdents() will return -ENOTDIR if this routine is not
- *	available.
- *
- *	Refer to sys_getdents() in fs/readdir.c
- *	sys_getdents() -> .
- *
- * PRE-CONDITIONS
- *	filp			Pointer to directory file.
- *	buf			Pointer to directory entry buffer.
- *	filldir			Pointer to filldir function.
- *
- * POST-CONDITIONS
- *	<return>		>=0 on success.
- *
- * HISTORY
- *	July 1, 1997 - Andrew E. Mileski
- *	Written, tested, and released.
- */
-
 static int udf_readdir(struct file *filp, void *dirent, filldir_t filldir)
 {
 	struct inode *dir = filp->f_path.dentry->d_inode;