ERP: Do not generate ERP keys when domain name is not specified

This commit adds changes to not generate ERP information if the domain
name is not specified in the EAP identity. keyName-NAI needs the realm
part and as such, it is reasonable to require the main EAP configuration
to provide that realm.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

src/eap_peer/eap.c

@@ -412,7 +412,7 @@ static char * eap_get_realm(struct eap_sm *sm, struct eap_peer_config *config)
 		}
 	}
 
-	return os_strdup("");
+	return NULL;
 }