[PATCH] convert ramfs to use __set_page_dirty_no_writeback

As pointed out by Hugh, ramfs would also benefit from using the new
set_page_dirty aop method for memory backed file systems.

Signed-off-by: Ken Chen <kenchen@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>