Some rptr/wptrs fields have different offsets and not all rings are pm4
so add a new nop field.
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NChristian König <deathsimple@vodafone.de>
Signed-off-by: NDave Airlie <airlied@redhat.com>