[PATCH] IB: Add ib_modify_mad API to MAD

Add new MAD layer call to modify (ib_modify_mad) the timeout of a sent MAD,
and simplify cancel code.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Hal Rosenstock <halr@voltaire.com>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>