Remove unused processDummy function

Removed unused processDummy function and related macro.

Author: njacazio

ALICE3/TableProducer/OTF/onTheFlyDetectorGeometryProvider.cxx

@@ -82,11 +82,6 @@ struct OnTheFlyDetectorGeometryProvider {
     pc.services().get<o2::framework::ControlService>().endOfStream();
     pc.services().get<o2::framework::ControlService>().readyToQuit(o2::framework::QuitRequest::Me);
   }
-
-  void processDummy(o2::aod::McCollisions const&)
-  {
-  }
-  PROCESS_SWITCH(OnTheFlyDetectorGeometryProvider, processDummy, "process dummy", false);
 };
 
 // #define VERIFY_ALICE3