Set initial endstops state

Addressing #8662

Marlin/endstops.h

@@ -28,6 +28,7 @@
 #define ENDSTOPS_H
 
 #include "enum.h"
+#include "MarlinConfig.h"
 
 class Endstops {
 
@@ -43,7 +44,15 @@ class Endstops {
     #endif
         current_endstop_bits, old_endstop_bits;
 
-    Endstops() {};
+    Endstops() {
+      enable_globally(
+        #if ENABLED(ENDSTOPS_ALWAYS_ON_DEFAULT)
+          true
+        #else
+          false
+        #endif
+      );
+    };
 
     /**
      * Initialize the endstop pins