futex.h updates:

- get rid of FUTEX_OWNER_PENDING - it's not used
- reduce ROBUST_LIST_LIMIT to a saner value
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>