clean up example to use CFG_TUD_ENABLED + CFG_TUD_MAX_SPEED instead of CFG_TUSB_RHPORT0_MODE

examples/device/audio_4_channel_mic/src/main.c

@@ -81,7 +81,8 @@ int main(void)
 {
   board_init();
 
-  tusb_init();
+  // init device stack on configured roothub port
+  tud_init(BOARD_TUD_RHPORT);
 
   // Init values
   sampFreq = AUDIO_SAMPLE_RATE;