drm/amdgpu: reserve less memory for PDE updates

Allocating 16KB was way to much, just use 2KB as a start for now.
Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Chunming Zhou <david1.zhou@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1390,7 +1390,7 @@ int amdgpu_vm_update_directories(struct amdgpu_device *adev,
 
 		params.func = amdgpu_vm_cpu_set_ptes;
 	} else {
-		ndw = 512 * 8;
+		ndw = 512;
 		r = amdgpu_job_alloc_with_ib(adev, ndw * 4, &job);
 		if (r)
 			return r;