drm/amdgpu: Stop reporting special chip memory pools as CPU memory in fdinfo

So far these specialized on chip memory pools were reported as system
memory (aka 'cpu') which is not correct and misleading. Lets remove that
and consider later making them visible as their own thing.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Suggested-by: Christian König <christian.koenig@amd.com>
Cc: Yunxiang Li <Yunxiang.Li@amd.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>