Fixes safe_delay() to be fully compatible with delay()

Marlin/Marlin.h

@@ -35,13 +35,11 @@
 
 #include "MarlinConfig.h"
 
-#include "fastio.h"
-
 #include "enum.h"
+#include "types.h"
+#include "fastio.h"
 #include "utility.h"
 
-typedef unsigned long millis_t;
-
 #ifdef USBCON
   #include "HardwareSerial.h"
   #if ENABLED(BLUETOOTH)

Marlin/utility.cpp

@@ -21,9 +21,10 @@
  */
 
 #include "Marlin.h"
+#include "utility.h"
 #include "temperature.h"
 
-void safe_delay(uint16_t ms) {
+void safe_delay(millis_t ms) {
   while (ms > 50) {
     ms -= 50;
     delay(50);

Marlin/utility.h

@@ -20,4 +20,9 @@
  *
  */
 
-void safe_delay(uint16_t ms);
+#ifndef __UTILITY_H__
+#define __UTILITY_H__
+
+void safe_delay(millis_t ms);
+
+#endif