shared/tinyusb: Fix build errors with CDC support disabled.

This commit makes possible building MicroPython with USB CDC support
disabled.

The original code does support such a configuration but missed a few
spots where build errors would arise.  These changes fix the remaining
issues, fixing also warnings caused by the changes needed to make the
build succeed.

Signed-off-by: Alessandro Gatti <a.gatti@frob.it>

shared/tinyusb/mp_usbd.h

@@ -38,13 +38,16 @@
 #ifndef NO_QSTR
 #include "tusb.h"
 #include "device/dcd.h"
+#include "class/cdc/cdc_device.h"
 #endif
 
 // Initialise TinyUSB device.
 static inline void mp_usbd_init_tud(void) {
     tusb_init();
+    #if MICROPY_HW_USB_CDC
     tud_cdc_configure_fifo_t cfg = { .rx_persistent = 0, .tx_persistent = 1 };
     tud_cdc_configure_fifo(&cfg);
+    #endif
 }
 
 // Run the TinyUSB device task