Fix logic in setting self.fsdp when it is False (huggingface#41974)

Co-authored-by: Roy Chan <[email protected]>

Author: 2 people

src/transformers/training_args.py

@@ -2655,7 +2655,7 @@ def set_dataloader(
         return self
 
     def _process_fsdp_args(self):
-        if self.fsdp is None:
+        if not self.fsdp:
             self.fsdp = []
         elif self.fsdp is True:
             self.fsdp = [FSDPOption.FULL_SHARD]