qnx: Removed unused bootstrap declaration.

QNX_bootstrap is the VideoBootStrap. QSAAUDIO_bootstrap is still there.

src/audio/SDL_sysaudio.h

@@ -205,7 +205,6 @@ extern AudioBootStrap FUSIONSOUND_bootstrap;
 extern AudioBootStrap ANDROIDAUDIO_bootstrap;
 extern AudioBootStrap PSPAUDIO_bootstrap;
 extern AudioBootStrap EMSCRIPTENAUDIO_bootstrap;
-extern AudioBootStrap QNX_bootstrap;
 
 #endif /* SDL_sysaudio_h_ */