fs/dcache: fix function param name in kernel-doc

Fix parameter name in kernel-doc notation (causes a warning).
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/dcache.c

@@ -1976,7 +1976,7 @@ static int prepend_path(const struct path *path, struct path *root,
  * __d_path - return the path of a dentry
  * @path: the dentry/vfsmount to report
  * @root: root vfsmnt/dentry (may be modified by this function)
- * @buffer: buffer to return value in
+ * @buf: buffer to return value in
  * @buflen: buffer length
  *
  * Convert a dentry into an ASCII path name.