only save training params on rank 0 (#415)

src/llama_recipes/utils/train_utils.py

@@ -255,7 +255,7 @@ def train(model, train_dataloader,eval_dataloader, tokenizer, optimizer, lr_sche
         results["metrics_filename"] = metrics_filename
 
     #saving the training params including fsdp setting for reference.
-    if train_config.enable_fsdp and not train_config.use_peft:
+    if train_config.enable_fsdp and not train_config.use_peft and rank==0:
         save_train_params(train_config, fsdp_config, rank)
 
     return results