py : add model class for Chameleon conversion (ggml-org#9683)

Author: nopperl

convert_hf_to_gguf.py

@@ -4162,7 +4162,8 @@ def modify_tensors(self, data_torch: Tensor, name: str, bid: int | None) -> Iter
         return super().modify_tensors(data_torch, name, bid)
 
 
-@Model.register("ChameleonForCausalLM")
+@Model.register("ChameleonForConditionalGeneration")
+@Model.register("ChameleonForCausalLM")  # obsolete
 class ChameleonModel(Model):
     model_arch = gguf.MODEL_ARCH.CHAMELEON