drm/amdgpu: implement 2+1 PD support for Raven v3

Instead of falling back to 2 level and very limited address space use
2+1 PD support and 128TB + 512GB of virtual address space.

v2: cleanup defines, rebase on top of level enum
v3: fix inverted check in hardware setup

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-and-Tested-by: Chunming Zhou <david1.zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>