Add datetime entities (#6513)

esphome/components/datetime/time_entity.cpp

@@ -94,8 +94,6 @@ void TimeEntityRestoreState::apply(TimeEntity *time) {
   time->publish_state();
 }
 
-#ifdef USE_TIME
-
 static const int MAX_TIMESTAMP_DRIFT = 900;  // how far can the clock drift before we consider
                                              // there has been a drastic time synchronization
 
@@ -103,7 +101,7 @@ void OnTimeTrigger::loop() {
   if (!this->parent_->has_state()) {
     return;
   }
-  ESPTime time = this->rtc_->now();
+  ESPTime time = this->parent_->rtc_->now();
   if (!time.is_valid()) {
     return;
   }
@@ -148,8 +146,6 @@ bool OnTimeTrigger::matches_(const ESPTime &time) const {
          time.second == this->parent_->second;
 }
 
-#endif
-
 }  // namespace datetime
 }  // namespace esphome