Remove unused config field from Gemma2 (#36672)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

vllm/model_executor/models/gemma2.py

@@ -63,7 +63,6 @@ class Gemma2MLP(nn.Module):
         self,
         hidden_size: int,
         intermediate_size: int,
-        hidden_act: str,
         hidden_activation: str,
         quant_config: QuantizationConfig | None = None,
         prefix: str = "",
@@ -83,11 +82,10 @@ class Gemma2MLP(nn.Module):
             quant_config=quant_config,
             prefix=f"{prefix}.down_proj",
         )
-        if not (hidden_act == hidden_activation == "gelu_pytorch_tanh"):
+        if not (hidden_activation == "gelu_pytorch_tanh"):
             raise ValueError(
                 "Gemma2 uses `gelu_pytorch_tanh` as the hidden activation "
-                "function. Please set `hidden_act` and `hidden_activation` to "
-                "`gelu_pytorch_tanh`."
+                "function. Please set `hidden_activation` to `gelu_pytorch_tanh`."
             )
         self.act_fn = GeluAndMul(approximate="tanh")
 
@@ -212,7 +210,6 @@ class Gemma2DecoderLayer(nn.Module):
         self.mlp = Gemma2MLP(
             hidden_size=self.hidden_size,
             intermediate_size=config.intermediate_size,
-            hidden_act=config.hidden_act,
             hidden_activation=config.hidden_activation,
             quant_config=quant_config,
             prefix=f"{prefix}.mlp",