CIK has new asynchronous DMA engines called sDMA
(system DMA).  Each engine supports 1 ring buffer
for kernel and gfx and 2 userspace queues for compute.

TODO: fill in the compute setup.

v2: update to the latest reset code
v3: remove ib_parse
v4: fix copy_dma()
v5: drop WIP compute sDMA queues
v6: rebase
v7: endian fixes for IB
v8: cleanup for release
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>