fix: force correct mixed dtype after HF load

modeling_hyena.py

@@ -45,8 +45,9 @@ class StripedHyenaModelForCausalLM(StripedHyenaPreTrainedModel):
             )
         self.vocab_size = vocab_size
         self.post_init()
+        self.force_dtype()
 
-    def post_init(self):
+    def force_dtype(self):
         self.backbone.to_bfloat16_except_poles_residues() 
         
     def _set_gradient_checkpointing(self, enable, gradient_checkpointing_func):