graph : add optional scale parameter to build_lora_mm [no ci] (#20427)

src/llama-graph.h

@@ -764,10 +764,11 @@ struct llm_graph_context {
              ggml_tensor * cur,
                      int   il) const;
 
-    // do mat_mul, while optionally apply lora
+    // do mat_mul, while optionally apply lora and per-tensor scale
     ggml_tensor * build_lora_mm(
               ggml_tensor * w,
-              ggml_tensor * cur) const;
+              ggml_tensor * cur,
+              ggml_tensor * w_s = nullptr) const;
 
     // do mat_mul_id, while optionally apply lora
     ggml_tensor * build_lora_mm_id(