drm/amdgpu: fix PRT teardown on VM fini v3

v2: new approach fixing this by registering a fence callback for
    all users of the VM on teardown
v3: agd: rebase

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
index 1dc5c10..57eaf71 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
@@ -164,7 +164,7 @@ struct amdgpu_vm_manager {
 
 	/* partial resident texture handling */
 	spinlock_t				prt_lock;
-	atomic_t				num_prt_mappings;
+	atomic_t				num_prt_users;
 };
 
 void amdgpu_vm_manager_init(struct amdgpu_device *adev);