Once added the above entry, try to reload the listener. Hope it helps !!
SID_LIST_LISTENER= (SID_LIST= (SID_DESC= (SID_NAME=<your exadata SID>) (ORACLE_HOME=<ORACLE_HOME path>) ) )
The listener runs out of the grid infrastructure home. I have tried to register the services by specifying LOCAL_LISTENER with reference to a network ALIAS in the database Oracle Home tnsnames.ora. I am running three listener, default listener listens to 1521, an additional listener on another IP segment listens to 1522 and one listener from the management network listens to port 1523.Shouldn't you be running the listener from Grid home? anyway for your question it does not matter from which home it is running.