skip NULL (for handling mixed slots)

radio/fhi_72/oaioran.c

@@ -319,7 +319,11 @@ int xran_fh_rx_read_slot(ru_info_t *ru, int *frame, int *slot){
 
             uint8_t *u8dptr;
             struct xran_prb_map *pRbMap = pPrbMap;
-            AssertFatal(ptr != NULL, "ptr NULL\n");
+            // for the moment, we just blindly go over all symbols. In mixed
+            // slots, xran returns NULL for DL symbols, so check that and
+            // continue in that case
+            if (ptr == NULL)
+              continue;
             AssertFatal(pos != NULL, "pos NULL\n");
             if(1){
                uint32_t idxElm = 0;