fdt_node_add_string_property
fdt_node_add_string_property(child, "device_type", "cpu");
fdt_node_add_string_property(child, "compatible", "arm,armv8");
fdt_node_add_string_property(child, "enable-method", "psci");
fdt_node_add_string_property(child, "compatible", "arm,gic-v2m-frame");
fdt_node_add_string_property(child, "compatible", "arm,gic-v3-its");