added KILL_PIN support / cleaned up manage_inactivity function definition

Marlin/planner.cpp

@@ -501,7 +501,7 @@ void plan_buffer_line(const float &x, const float &y, const float &z, const floa
   // Rest here until there is room in the buffer.
   while(block_buffer_tail == next_buffer_head) { 
     manage_heater(); 
-    manage_inactivity(1); 
+    manage_inactivity(); 
     LCD_STATUS;
   }