drm/amdkfd: Move gfx9.4.3 and gfx 9.5 MQD to HBM

drm/amdkfd: Move gfx9.4.3 and gfx 9.5 MQD to HBM

To reduce queue switch latency further, move MQD to VRAM domain, CP
access MQD and control stack via FB aperture, this requires contiguous
pages.

After MQD is initialized, updated or restored, flush HDP to guarantee
the data is written to HBM and GPU cache is invalidated, then CP will
read the new MQD.

Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>