Update globals.h

As mentioned by Makuna of RTC library project.

include/globals.h

@@ -6,8 +6,7 @@
 
 // Time functions
 #ifdef HAS_RTC
-#include <RtcUtility.h>
-#include <RtcDateTime.h>
+#include <RtcDS3231.h>
 #endif
 #include <Ticker.h>
 
@@ -114,4 +113,4 @@ typedef struct {
 
 extern char clientId[20]; // unique clientID
 
-#endif
+#endif