model : support DSpark for LFM2 models (#27383)

src/llama-arch.cpp

@@ -1032,6 +1032,8 @@ bool llm_arch_supports_rs_rollback(const llm_arch & arch) {
         case LLM_ARCH_DEEPSEEK4:
         case LLM_ARCH_NEMOTRON_H:
         case LLM_ARCH_NEMOTRON_H_MOE:
+        case LLM_ARCH_LFM2:
+        case LLM_ARCH_LFM2MOE:
             return true;
         default:
             return false;