drm/amdgpu: Restore HQD persistent state register

On GFX v9.4.3, compute queue MQD is populated using the values in HQD
persistent state register. Hence don't clear the values on module
unload, instead restore it to the default reset value so that MQD is
initialized correctly during next module load. In particular, preload
flag needs to be set on compute queue MQD, otherwise it could cause
uninitialized values being used at device reset state resulting in EDC.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Asad Kamal <asad.kamal@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>