py/objint: from_bytes, to_bytes: Require byteorder arg, require "little".

CPython requires byteorder arg, make uPy compatible. As we support only
"little", error out on anything else.

py/objint.c

@@ -383,10 +383,14 @@ mp_obj_t mp_obj_int_binary_op_extra_cases(mp_uint_t op, mp_obj_t lhs_in, mp_obj_
 // this is a classmethod
 STATIC mp_obj_t int_from_bytes(size_t n_args, const mp_obj_t *args) {
     // TODO: Support long ints
-    // TODO: Support byteorder param (assumes 'little' at the moment)
+    // TODO: Support byteorder param
     // TODO: Support signed param (assumes signed=False at the moment)
     (void)n_args;
 
+    if (args[2] != MP_OBJ_NEW_QSTR(MP_QSTR_little)) {
+        mp_not_implemented("");
+    }
+
     // get the buffer info
     mp_buffer_info_t bufinfo;
     mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_READ);
@@ -400,14 +404,18 @@ STATIC mp_obj_t int_from_bytes(size_t n_args, const mp_obj_t *args) {
     return mp_obj_new_int_from_uint(value);
 }
 
-STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(int_from_bytes_fun_obj, 2, 3, int_from_bytes);
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(int_from_bytes_fun_obj, 3, 4, int_from_bytes);
 STATIC MP_DEFINE_CONST_CLASSMETHOD_OBJ(int_from_bytes_obj, MP_ROM_PTR(&int_from_bytes_fun_obj));
 
 STATIC mp_obj_t int_to_bytes(size_t n_args, const mp_obj_t *args) {
-    // TODO: Support byteorder param (assumes 'little')
+    // TODO: Support byteorder param
     // TODO: Support signed param (assumes signed=False)
     (void)n_args;
 
+    if (args[2] != MP_OBJ_NEW_QSTR(MP_QSTR_little)) {
+        mp_not_implemented("");
+    }
+
     mp_uint_t len = MP_OBJ_SMALL_INT_VALUE(args[1]);
 
     vstr_t vstr;
@@ -427,7 +435,7 @@ STATIC mp_obj_t int_to_bytes(size_t n_args, const mp_obj_t *args) {
 
     return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(int_to_bytes_obj, 2, 4, int_to_bytes);
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(int_to_bytes_obj, 3, 4, int_to_bytes);
 
 STATIC const mp_rom_map_elem_t int_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_from_bytes), MP_ROM_PTR(&int_from_bytes_obj) },