Fix AUTO_POWER_CONTROL compile error

Counterpart to #11467

Co-Authored-By: lsellens <lsellens@users.noreply.github.com>

Marlin/src/feature/power.cpp

   ) return true;
 
   HOTEND_LOOP() if (thermalManager.degTargetHotend(e) > 0) return true;
-  if (thermalManager.degTargetBed() > 0) return true;
+
+  #if HAS_HEATED_BED
+    if (thermalManager.degTargetBed() > 0) return true;
+  #endif
 
   return false;
 }