Fix SD_FINISHED_RELEASECOMMAND bug

Fixes #17401 bug that was introduced in 8f26c3a

Marlin/src/inc/Conditionals_adv.h

@@ -68,6 +68,15 @@
   #define HAS_FILAMENT_SENSOR 1
 #endif
 
+// Let SD_FINISHED_RELEASECOMMAND stand in for SD_FINISHED_STEPPERRELEASE
+#if ENABLED(SD_FINISHED_STEPPERRELEASE)
+  #ifndef SD_FINISHED_RELEASECOMMAND
+    #define SD_FINISHED_RELEASECOMMAND "M84" // planner.finish_and_disable()
+  #endif
+#else
+  #undef SD_FINISHED_RELEASECOMMAND
+#endif
+
 #if EITHER(SDSUPPORT, LCD_SET_PROGRESS_MANUALLY)
   #define HAS_PRINT_PROGRESS 1
 #endif