RTC: Fix for TASKS_TRIGOVRFLW with stopped counter

nhw_rtc_TASKS_TRIGOVRFLW() was assuming the task
would only be called if the timer is running, but that
is not correct. The timer may be stopped.
Let's fix it.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>

src/HW_models/NHW_RTC.c

@@ -547,6 +547,7 @@ static void nhw_rtc_TASKS_TRIGOVRFLW(uint rtc) {
 
   /* Pre-scaler value is latched to an internal register on tasks START, CLEAR, and TRIGOVRFLW */
   nhw_rtc_st[rtc].PRESC = NRF_RTC_regs[rtc].PRESCALER;
+  nhw_rtc_st[rtc].counter_at_stop = RTC_TRIGGER_OVERFLOW_COUNTER_VALUE;
   nhw_rtc_set_counter(rtc, RTC_TRIGGER_OVERFLOW_COUNTER_VALUE);
 }