drm syncobj - final posting I hope

[Dave Airlie]

I've fixed up a few things in here from Daniel's comments,
Daniel I didn't change things exactly as suggested but I removed
fd_flags from API completely.

Christian, I think I got the post deps hook in the right place
now in the amdgpu patch.

Would be nice if someone can validate the timeout stuff
in the second patch makes sense, I've decided to stick to
an absolute timeout.

I will probably at least merge the first 3 into drm-next, and
we can work out what to do with the two amdgpu ones.

Dave.