Allow SD_FINISHED_RELEASECOMMAND to be undefined

Marlin/Conditionals.h

   #endif
 
   #ifdef ULTIPANEL
-   #undef SDCARDDETECTINVERTED
+    #undef SDCARDDETECTINVERTED
   #endif
 
   // Power Signal Control Definitions

Marlin/stepper.cpp

   {
     current_block = NULL;
     plan_discard_current_block();
-    if ((cleaning_buffer_counter == 1) && (SD_FINISHED_STEPPERRELEASE)) enquecommands_P(PSTR(SD_FINISHED_RELEASECOMMAND));
+    #ifdef SD_FINISHED_RELEASECOMMAND
+      if ((cleaning_buffer_counter == 1) && (SD_FINISHED_STEPPERRELEASE)) enquecommands_P(PSTR(SD_FINISHED_RELEASECOMMAND));
+    #endif
     cleaning_buffer_counter--;
     OCR1A = 200;
     return;