[BugFix] Fix minimax m2 model rotary_dim (#30384)

Signed-off-by: xuebi <xuebi@minimaxi.com>
Co-authored-by: xuebi <xuebi@minimaxi.com>

vllm/model_executor/models/minimax_m2.py

@@ -201,7 +201,7 @@ class MiniMaxM2Attention(nn.Module):
 
         self.rotary_emb = get_rope(
             self.head_dim,
-            rotary_dim=rotary_dim,
+            rotary_dim=self.head_dim,
             max_position=max_position_embeddings,
             rope_parameters=rope_parameters,
         )