ofw_finddevice
chosenh = ofw_finddevice("/chosen");
static ofwh_t ofw_finddevice(const char *);
OFWMETHOD(ofw_finddevice, ofw_fdt_finddevice),
OFWMETHOD(ofw_finddevice, ofw_std_finddevice),
OFWMETHOD(ofw_finddevice, ofw_real_finddevice),
phandle_t ofw_finddevice(int, const char *);
n = start == NULL ? ofw_root(fd) : ofw_finddevice(fd, start);