drm/amdgpu: set at least the node size in the gtt manager

Otherwise the new VM code becomes confused.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Edward O'Callaghan <funfunctor@folklore1984.net>
Tested-by: Mike Lothian <mike@fireburn.co.uk>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -168,6 +168,7 @@ static int amdgpu_gtt_mgr_new(struct ttm_mem_type_manager *man,
 		return -ENOMEM;
 
 	node->start = AMDGPU_BO_INVALID_OFFSET;
+	node->size = mem->num_pages;
 	mem->mm_node = node;
 
 	if (place->fpfn || place->lpfn || place->flags & TTM_PL_FLAG_TOPDOWN) {