[Bugfix] Correct LayerNorm epsilon parameter in modernbert.py (#27008)

Signed-off-by: bogdanm <152898065+bogdan01m@users.noreply.github.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

vllm/model_executor/models/modernbert.py

@@ -39,9 +39,12 @@ class ModernBertEmbeddings(nn.Module):
         self.tok_embeddings = VocabParallelEmbedding(
             config.vocab_size, config.hidden_size
         )
-        self.norm = nn.LayerNorm(
-            config.hidden_size, eps=config.layer_norm_eps, bias=config.norm_bias
+        eps = (
+            getattr(config, "norm_eps", None)
+            or getattr(config, "layer_norm_eps", None)
+            or 1e-5
         )
+        self.norm = nn.LayerNorm(config.hidden_size, eps=eps, bias=config.norm_bias)
 
     def get_input_embeddings(self, input_ids: torch.Tensor) -> torch.Tensor:
         return self.tok_embeddings(input_ids)