SDMA packets which use dmaVirtWrites call their completion event before
the write takes place in the Ruby protocol. This causes a use-after-free
issue corruption random memory locations leading to random errors. This
commit adds a cleanup event for each packet that uses DMA and sets the
cleanup latency as 10000 ticks. In atomic mode, the writes complete
exactly 2000 ticks after the completion event is called and therefore a
fixed latency can be used. This is not tested with timing mode, which
does not work with GPUFS at the moment, so a warning is added to give an
idea where to look in case the same issue occurs once timing mode is
supported.
Change-Id: I9ee2689f2becc46bb7794b18b31205f1606109d8