wasapi: AvSetMmThreadCharacteristicsW takes an LPCWSTR param, not LPWSTR

src/audio/wasapi/SDL_wasapi_win32.c

@@ -53,7 +53,7 @@ static IMMDeviceEnumerator *enumerator = NULL;
 
 /* handle to Avrt.dll--Vista and later!--for flagging the callback thread as "Pro Audio" (low latency). */
 static HMODULE libavrt = NULL;
-typedef HANDLE(WINAPI *pfnAvSetMmThreadCharacteristicsW)(LPWSTR, LPDWORD);
+typedef HANDLE(WINAPI *pfnAvSetMmThreadCharacteristicsW)(LPCWSTR, LPDWORD);
 typedef BOOL(WINAPI *pfnAvRevertMmThreadCharacteristics)(HANDLE);
 static pfnAvSetMmThreadCharacteristicsW pAvSetMmThreadCharacteristicsW = NULL;
 static pfnAvRevertMmThreadCharacteristics pAvRevertMmThreadCharacteristics = NULL;