[Linaro-mm-sig] completely rework the dma_resv semantic

Hi guys,

by now that should be a rather well known set of changes.

The basic idea is that instead of the fixed exclusive/shared classes we now attach an usage to each fence in the dma_resv object describing how the operation represented by the fence is using the resources protected by the dma_resv.

I've addressed quite a bunch of comments already and I think this set has already been discussed quite well now. As improvement to the last version I've now added CCs for all the relevant maintainers to the patches changing some functionality inside drivers.

Please review and comment, Christian.