Changed the DSP ROM warning from a panic alert to an on-screen message.

Source/DSPTool/Src/DSPTool.cpp

@@ -11,6 +11,7 @@
 // Stub out the dsplib host stuff, since this is just a simple cmdline tools.
 u8 DSPHost_ReadHostMemory(u32 addr) { return 0; }
 void DSPHost_WriteHostMemory(u8 value, u32 addr) {}
+void DSPHost_OSD_AddMessage(const std::string& str, u32 ms) {}
 bool DSPHost_OnThread() { return false; }
 bool DSPHost_Wii() { return false; }
 void DSPHost_CodeLoaded(const u8 *ptr, int size) {}