[Add] software simulator add

labus/include/serial.hh

@@ -0,0 +1,10 @@
+#pragma once
+
+#include <device.hh>
+
+class Serial : public WRDevice<Serial> {
+public:
+  Serial(size_t siz);
+
+  void write(char *buf, size_t addr, size_t len);
+};