esp32/machine_uart: Implement UART.deinit() method.

ports/esp32/machine_uart.c

@@ -286,6 +286,13 @@ STATIC mp_obj_t machine_uart_init(size_t n_args, const mp_obj_t *args, mp_map_t
 }
 MP_DEFINE_CONST_FUN_OBJ_KW(machine_uart_init_obj, 1, machine_uart_init);
 
+STATIC mp_obj_t machine_uart_deinit(mp_obj_t self_in) {
+    machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    uart_driver_delete(self->uart_num);
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_deinit_obj, machine_uart_deinit);
+
 STATIC mp_obj_t machine_uart_any(mp_obj_t self_in) {
     machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
     size_t rxbufsize;
@@ -327,7 +334,7 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_sendbreak_obj, machine_uart_sendbr
 
 STATIC const mp_rom_map_elem_t machine_uart_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&machine_uart_init_obj) },
-
+    { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&machine_uart_deinit_obj) },
     { MP_ROM_QSTR(MP_QSTR_any), MP_ROM_PTR(&machine_uart_any_obj) },
     { MP_ROM_QSTR(MP_QSTR_read), MP_ROM_PTR(&mp_stream_read_obj) },
     { MP_ROM_QSTR(MP_QSTR_readline), MP_ROM_PTR(&mp_stream_unbuffered_readline_obj) },