DS1307: Change year bias to 1968 which is a leap year juse like 2000

drivers/timers/ds3231.c

@@ -392,9 +392,11 @@ int up_rtc_getdatetime(FAR struct tm *tp)
       tp->tm_year = tmp + 100;
     }
 #else
-  /* No century indicator.  The RTC will hold years since 1970 */
+  /* No century indicator.  The RTC will hold years since 1968 (a leap year like
+   * 2000)
+   */
 
-  tp->tm_year = tmp + 70;
+  tp->tm_year = tmp + 68;
 #endif
 
   rtc_dumptime(tp, "Returning");
@@ -512,10 +514,10 @@ int up_rtc_settime(FAR const struct timespec *tp)
     }
 
 #else
-  /* Use years since 1970 */
+  /* Use years since 1968 (a leap year like 2000) */
 
   century = 0;
-  year    = newtm.tm_year - 70;
+  year    = newtm.tm_year - 68;
 #endif
 
   /* Save the month (1-12) with century */

sched/clock/clock_initialize.c

@@ -201,11 +201,11 @@ static void clock_inittime(void)
 
 void clock_initialize(void)
 {
+#if defined(CONFIG_RTC) && !defined(CONFIG_RTC_EXTERNAL)
   /* Initialize the internal RTC hardware.  Initialization of external RTC
    * must be deferred until the system has booted.
    */
 
-#if defined(CONFIG_RTC) && !defined(CONFIG_RTC_EXTERNAL)
   up_rtcinitialize();
 #endif