jbd: remove excess kernel-doc notation

Remove excess kernel-doc from fs/jbd/transaction.c:

Warning(linux-2.6.28-git5//fs/jbd/transaction.c:764): Excess function parameter 'credits' description in 'journal_get_write_access'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/jbd/transaction.c

@@ -754,7 +754,6 @@ out:
  * int journal_get_write_access() - notify intent to modify a buffer for metadata (not data) update.
  * @handle: transaction to add buffer modifications to
  * @bh:     bh to be used for metadata writes
- * @credits: variable that will receive credits for the buffer
  *
  * Returns an error code or 0 on success.
  *