common: Enforce fastmem for nce usage

src/common/settings.cpp

@@ -160,7 +160,7 @@ static bool is_nce_enabled = false;
 
 void SetNceEnabled(bool is_39bit) {
     const bool is_nce_selected = values.cpu_backend.GetValue() == CpuBackend::Nce;
-    is_nce_enabled = is_nce_selected && is_39bit;
+    is_nce_enabled = IsFastmemEnabled() && is_nce_selected && is_39bit;
     if (is_nce_selected && !is_nce_enabled) {
         LOG_WARNING(
             Common,