message: remove mqtt unused code
diff: @@ -29,7 +29,7 @@ void swMqtt_set_protocol(swProtocol *protocol) {
  protocol->get_package_length = swMqtt_get_package_length;
  }
  -static sw_inline ssize_t swMqtt_get_length(const char *data, uint32_t size, ssize_t *count) {
  +static sw_inline ssize_t swMqtt_get_length(const char *data, ssize_t *count) {
  uint8_t byte;
  int mul = 1;
  ssize_t length = 0;
  @@ -70,6 +70,6 @@ ssize_t swMqtt_get_package_length(swProtocol *protocol, swSocket *conn, const ch
  return 0;
  }
  ssize_t count = 0;
  - ssize_t length = swMqtt_get_length(data, size, &count);
  + ssize_t length = swMqtt_get_length(data, &count);
  return length + count + 1;
  }
  