drm/amdgpu: implement burst NOP for SDMA

Customize the insert_nop func for SDMA rings, and use burst NOP for
ring/IB submissions in other places as well

Signed-off-by: Jammy Zhou <Jammy.Zhou@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
3 files changed