sched_harq: fix uninitialized values in HARQ

detected with Valgrind memcheck

srsenb/hdr/stack/mac/sched_ue_ctrl/sched_harq.h

@@ -47,17 +47,17 @@ protected:
 
   enum ack_t { NACK, ACK };
 
-  srslog::basic_logger*           logger;
+  srslog::basic_logger*               logger    = nullptr;
-  bool                            ack_state[SRSRAN_MAX_TB];
+  std::array<bool, SRSRAN_MAX_TB>     ack_state = {};
-  bool                            active[SRSRAN_MAX_TB];
+  std::array<bool, SRSRAN_MAX_TB>     active    = {};
   std::array<bool, SRSRAN_MAX_TB>     ndi       = {};
-  uint32_t                        id;
+  uint32_t                            id        = 0;
   uint32_t                            max_retx  = 5;
-  uint32_t                        n_rtx[SRSRAN_MAX_TB];
+  std::array<uint32_t, SRSRAN_MAX_TB> n_rtx     = {};
-  uint32_t                        tx_cnt[SRSRAN_MAX_TB];
+  std::array<uint32_t, SRSRAN_MAX_TB> tx_cnt    = {};
+  std::array<int, SRSRAN_MAX_TB>      last_mcs  = {};
+  std::array<int, SRSRAN_MAX_TB>      last_tbs  = {};
   srsran::tti_point                   tti;
-  int                             last_mcs[SRSRAN_MAX_TB];
-  int                             last_tbs[SRSRAN_MAX_TB];
 };
 
 class dl_harq_proc : public harq_proc