[BUGFIX] llama_4_scaling wrongly passed to DeepseekAttention (#29908)

Signed-off-by: juliendenize <julien.denize@mistral.ai>
(cherry picked from commit 5e5646e2)

vllm/model_executor/models/deepseek_v2.py

@@ -1135,6 +1135,8 @@ class DeepseekV2DecoderLayer(nn.Module):
             dim == 0 for dim in (qk_nope_head_dim, qk_rope_head_dim)
         )
 
+        self.use_mha = use_mha
+
         if use_mha:
             attn_cls = DeepseekAttention
         elif model_config.use_mla:
@@ -1196,11 +1198,14 @@ class DeepseekV2DecoderLayer(nn.Module):
             hidden_states = self.input_layernorm(hidden_states)
         else:
             hidden_states, residual = self.input_layernorm(hidden_states, residual)
-        hidden_states = self.self_attn(
-            positions=positions,
-            hidden_states=hidden_states,
-            llama_4_scaling=llama_4_scaling,
-        )
+
+        attn_kwargs = {
+            "positions": positions,
+            "hidden_states": hidden_states,
+        }
+        if not self.use_mha:
+            attn_kwargs["llama_4_scaling"] = llama_4_scaling
+        hidden_states = self.self_attn(**attn_kwargs)
 
         if (
             not isinstance(self.self_attn, DeepseekAttention)