enable USBMC for uno r4, add board_init_after_tusb() API

add BOARD_UPPERCASE for board detection

examples/host/cdc_msc_hid/src/main.c

@@ -48,6 +48,10 @@ int main(void)
   // init host stack on configured roothub port
   tuh_init(BOARD_TUH_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   while (1)
   {
     // tinyusb host task