gNB: fix allocation of RC.gNB[] array

If the array of pointers is allocated using malloc(), it is not guaranteed that the pointers are NULL, so the actual PHY_VARS_gNB might nit be allocated correctly!
Also replace a malloc() + memset() combination by just a calloc().

executables/nr-gnb.c

@@ -468,15 +468,14 @@ void init_gNB(int single_thread_flag,int wait_for_sync) {
   PHY_VARS_gNB *gNB;
 
   if (RC.gNB == NULL) {
-    RC.gNB = (PHY_VARS_gNB **) malloc((1+RC.nb_nr_L1_inst)*sizeof(PHY_VARS_gNB *));
+    RC.gNB = (PHY_VARS_gNB **) calloc(1+RC.nb_nr_L1_inst, sizeof(PHY_VARS_gNB *));
     LOG_I(PHY,"gNB L1 structure RC.gNB allocated @ %p\n",RC.gNB);
   }
 
   for (inst=0; inst<RC.nb_nr_L1_inst; inst++) {
 
     if (RC.gNB[inst] == NULL) {
-      RC.gNB[inst] = (PHY_VARS_gNB *) malloc(sizeof(PHY_VARS_gNB));
-      memset((void*)RC.gNB[inst],0,sizeof(PHY_VARS_gNB));
+      RC.gNB[inst] = (PHY_VARS_gNB *) calloc(1, sizeof(PHY_VARS_gNB));
       LOG_I(PHY,"[nr-gnb.c] gNB structure RC.gNB[%d] allocated @ %p\n",inst,RC.gNB[inst]);
     }
     gNB                     = RC.gNB[inst];