replace hardcoded SPI DMA parameter

Author: arktrin

lvgl_helpers.c

@@ -176,7 +176,7 @@ bool lvgl_spi_driver_init(int host,
 
     ESP_LOGI(TAG, "Initializing SPI bus...");
     #if defined (CONFIG_IDF_TARGET_ESP32C3)
-    dma_channel = 3;
+    dma_channel = SPI_DMA_CH_AUTO;
     #endif
     esp_err_t ret = spi_bus_initialize(host, &buscfg, (spi_dma_chan_t)dma_channel);
     assert(ret == ESP_OK);