drm/amdgpu:no need to involv HDP in KIQ

1,KIQ won't touch VRAM so no need to involv HDP flush/invalidate at all.
2,According to CP hw designer KIQ better not use any PM4 package lead to wait behave.

Signed-off-by: Monk Liu <Monk.Liu@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>