fdt_grab_space_
nh = fdt_grab_space_(fdt, sizeof(*nh) + FDT_TAGALIGN(namelen));
en = fdt_grab_space_(fdt, FDT_TAGSIZE);
prop = fdt_grab_space_(fdt, sizeof(*prop) + FDT_TAGALIGN(len));
end = fdt_grab_space_(fdt, sizeof(*end));