fdt_next_subnode
cpus_subnode_offset = fdt_next_subnode(fdt, prev_node_offset);
subnode = fdt_next_subnode(fdt, subnode)) {
off = fdt_next_subnode(root_fdt, off)) {
int fdt_next_subnode(const void *fdt, int offset);
node = fdt_next_subnode(fdt, node))