fix post_init deepseek v3

exo/inference/mlx/models/deepseek_v3.py

@@ -18,7 +18,6 @@ class ModelArgs(V3ModelArgs):
   shard: Shard = field(default_factory=lambda: Shard("", 0, 0, 0))
 
   def __post_init__(self):
-    super().__post_init__()
     if isinstance(self.shard, Shard):
       return
     if not isinstance(self.shard, dict):