libs/libc/unistd/lib_alarm.c,sched/timer/timer_getitimer.c: Silence a

warning with struct initialization.

libs/libc/unistd/lib_alarm.c

@@ -70,12 +70,14 @@ unsigned int alarm(unsigned int seconds)
 {
   struct itimerval value =
   {
-    0, 0
+    {0, 0},
+    {0, 0}
   };
 
   struct itimerval ovalue =
   {
-    0, 0
+    {0, 0},
+    {0, 0}
   };
 
   value.it_value.tv_sec = seconds;

sched/timer/timer_getitimer.c

@@ -86,7 +86,8 @@ int getitimer(int which, FAR struct itimerval *value)
   FAR struct tcb_s *rtcb = this_task();
   struct itimerspec spec =
   {
-    0, 0
+    {0, 0},
+    {0, 0}
   };
 
   int ret = OK;