add spi deinit for sleep

src/spislave.cpp

@@ -106,7 +106,9 @@ void spi_slave_task(void *param) {
   }
 }
 
-esp_err_t spi_init() {
+void spi_deinit(void) { vTaskDelete(spiTask); }
+
+esp_err_t spi_init(void) {
   _ASSERT(SEND_QUEUE_SIZE > 0);
   SPISendQueue = xQueueCreate(SEND_QUEUE_SIZE, sizeof(MessageBuffer_t));
   if (SPISendQueue == 0) {