drm/amdgpu: Make CPX mode auto default in NPS4

On GFXIP9.4.3, make CPX mode as the default compute mode if the node is
setup in NPS4 memory partition mode. This change is only applicable for
dGPU, for APU, continue to use TPX mode.

Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>