tty:support tty c_cc VMIN & VTIME

Signed-off-by: anjiahao <anjiahao@xiaomi.com>

drivers/serial/serial_dma.c

@@ -336,7 +336,20 @@ void uart_recvchars_done(FAR uart_dev_t *dev)
    * incoming data available.
    */
 
+  if (rxbuf->head >= rxbuf->tail)
+    {
+      nbytes = rxbuf->head - rxbuf->tail;
+    }
+  else
+    {
+      nbytes = rxbuf->size - rxbuf->tail + rxbuf->head;
+    }
+
+#ifdef CONFIG_SERIAL_TERMIOS
+  if (nbytes >= dev->minrecv)
+#else
   if (nbytes)
+#endif
     {
       uart_datareceived(dev);
     }