Revert "drm/amdgpu/gfx8: Fix compute ring failure after resetting"

This reverts commit 75737cb4.

Fixes compute rings test failure on bare metal during full GPU reset.

RCA:
the ring buffer has to be filled with valid packets (such as NOPs) first
before submitting MAP_QUEUEs packet into KIQ. Once a compute engine is mapped,
it will immediately execute the ring buffer if the RTPR is not equal to the
WTPR from the MQD. It could lead to engine hang if the ring buffer filled
with random data.

Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>