remove start_background_system from eNB softmodem

This is only needed by the UE code, to setup IP settings.
The eNB does not need this. (To be reverted if this is
wrong.)

targets/RT/USER/lte-softmodem.c

@@ -904,7 +904,6 @@ int main( int argc, char **argv )
   int ret;
 #endif
 
-  start_background_system();
   if ( load_configmodule(argc,argv) == NULL) {
     exit_fun("[SOFTMODEM] Error, configuration module init failed\n");
   }