[ofw] patch: Fix a race in the cl_timer code that caused deadlocks in opensm

[Hefty, Sean]

> Yes, we need to have a clear expectation of how the timer behaves.  It
> seems that the current issue is rooted in the fact that opensm made
> assumptions about timers based on the Linux implementation, and that the
> Windows timer implementation is *much* more relaxed in its operation.

The behavior between user space and the kernel will likely be different.  For the kernel, we should toss the abstraction completely, but for now, I assumed that the code behaved like the underlying kernel timers.  E.g. start implicitly cancels the timer if it's running.