Removed OAI exit in mac_rlc_data_req when no RB is present

- this prevents crashes when the function is called for LCIDs that have no RB
- and simply print error message and return 0 when no RB is found

openair2/LAYER2/nr_rlc/nr_rlc_oai_api.c

@@ -208,7 +208,10 @@ tbs_size_t mac_rlc_data_req(
   switch (channel_idP) {
   case 1 ... 3: rb = ue->srb[channel_idP - 1]; break;
   case 4 ... 8: rb = ue->drb[channel_idP - 4]; break;
-  default:      rb = NULL;                     break;
+  default:
+  rb = NULL;
+  LOG_E(RLC, "In %s:%d:%s: data request for unknown RB with LCID 0x%02x !\n", __FILE__, __LINE__, __FUNCTION__, channel_idP);
+  break;
   }
 
   if (rb != NULL) {
@@ -216,8 +219,6 @@ tbs_size_t mac_rlc_data_req(
     maxsize = tb_sizeP;
     ret = rb->generate_pdu(rb, buffer_pP, maxsize);
   } else {
-    LOG_E(RLC, "%s:%d:%s: fatal: data req for unknown RB, channel_idP: %d\n", __FILE__, __LINE__, __FUNCTION__, channel_idP);
-    exit(1);
     ret = 0;
   }