drm/amdgpu: use pd addr based on gart level page table

With a recent gart page table re-construction, the gart page
table is now 2-level for some ASICs: PDB0->PTB.
In the case of 2-level gart page table, the page_table_base
of vmid0 should point to PDB0 instead of PTB.
Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Oak Zeng <Oak.Zeng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c

@@ -2057,7 +2057,8 @@ int amdgpu_copy_buffer(struct amdgpu_ring *ring, uint64_t src_offset,
 		return r;
 
 	if (vm_needs_flush) {
-		job->vm_pd_addr = amdgpu_gmc_pd_addr(adev->gart.bo);
+		job->vm_pd_addr = amdgpu_gmc_pd_addr(adev->gmc.pdb0_bo ?
+					adev->gmc.pdb0_bo : adev->gart.bo);
 		job->vm_needs_flush = true;
 	}
 	if (resv) {