fix uninit vars reported by Coverity

srsue/hdr/stack/mac/mac.h

@@ -121,7 +121,7 @@ private:
   rrc_interface_mac*                         rrc_h   = nullptr;
   stack_interface_mac*                       stack_h = nullptr;
   srslte::log_ref                            log_h;
-  mac_interface_phy_lte::mac_phy_cfg_mbsfn_t phy_mbsfn_cfg;
+  mac_interface_phy_lte::mac_phy_cfg_mbsfn_t phy_mbsfn_cfg = {};
 
   // RNTI search window scheduling
   int si_window_length = -1, si_window_start = -1;

srsue/hdr/stack/upper/nas_common.h

@@ -25,8 +25,8 @@
 namespace srsue {
 
 typedef struct {
-  int airplane_t_on_ms;
-  int airplane_t_off_ms;
+  int airplane_t_on_ms  = -1;
+  int airplane_t_off_ms = -1;
 } nas_sim_args_t;
 
 class nas_args_t

srsue/test/mac_test.cc

@@ -372,7 +372,7 @@ public:
   }
 
 private:
-  phy_interface_mac_lte* phy_h;
+  phy_interface_mac_lte* phy_h = nullptr;
   mac*                   mac_h = nullptr;
 };