RTC driver: Needs to initialize state structure to zero on initalization

arch

@@ -1 +1 @@
-Subproject commit c71c24971d1ff233a59a85c7ad65c81bdaeaa60b
+Subproject commit c4f77e7d8721f62631c4e90aeb4629db9c7cbee0

drivers/timers/rtc.c

@@ -577,7 +577,7 @@ int rtc_initialize(int minor, FAR struct rtc_lowerhalf_s *lower)
 
   /* Allocate an upper half container structure */
 
-  upper = (FAR struct rtc_upperhalf_s *)kmm_malloc(sizeof(struct rtc_upperhalf_s));
+  upper = (FAR struct rtc_upperhalf_s *)kmm_zalloc(sizeof(struct rtc_upperhalf_s));
   if (!upper)
     {
       return -ENOMEM;