flous MS_NODIRATIME assignment

MS_NOATIME implies MS_NODIRATIME

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Eric Van Hensbergen <ericvh@ericvh.myip.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Cu ••#x