Add missing file

src/common/3gpp_24.501.h

+/*
+ * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenAirInterface Software Alliance licenses this file to You under
+ * the OAI Public License, Version 1.1  (the "License"); you may not use this
+ * file except in compliance with the License. You may obtain a copy of the
+ * License at
+ *
+ *      http://www.openairinterface.org/?page_id=698
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *-------------------------------------------------------------------------------
+ * For more information about the OpenAirInterface (OAI) Software Alliance:
+ *      contact@openairinterface.org
+ */
+
+#ifndef FILE_3GPP_24_501_SEEN
+#define FILE_3GPP_24_501_SEEN
+
+// Table 10.3.1 @3GPP TS 24.501 V16.1.0 (2019-06)
+#define T3512_TIMER_VALUE_SEC 3240  // 54 minutes
+#define T3512_TIMER_VALUE_MIN 54    // 54 minutes
+#define MOBILE_REACHABLE_TIMER_NO_EMERGENCY_SERVICES_MIN                       \
+  (T3512_TIMER_VALUE_MIN + 4)  // T3512 + 4, not for emergency services
+#endif