BugFix:uart_ops_s portion of cdcacm will not be initalized with correct functions if CONFIG_SERIAL_DMA is lit.

This fixes the issses in a C99 compatible way

drivers/usbdev/cdcacm.c

@@ -242,6 +242,12 @@ static const struct uart_ops_s g_uartops =
   NULL,                  /* rxavailable */
 #ifdef CONFIG_SERIAL_IFLOWCONTROL
   cdcuart_rxflowcontrol, /* rxflowcontrol */
+#endif
+#ifdef CONFIG_SERIAL_DMA
+  NULL,                  /* dmasend */
+  NULL,                  /* dmareceive */
+  NULL,                  /* dmarxfree */
+  NULL,                  /* dmatxavail */
 #endif
   NULL,                  /* send */
   cdcuart_txint,         /* txinit */