drm/amdkfd: DIQ should not use HIQ way to allocate memory

In the mqd_diq_sdma buffer, there should be only one HIQ mqd. All DIQs
should be allocated somewhere else using the regular way.

Signed-off-by: Yong Zhao <Yong.Zhao@amd.com>
Reviewed-by: Oak Zeng <Oak.Zeng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>