Flax `from_pretrained`: clean up `mismatched_keys`. (#630)

Flax from_pretrained: clean up `mismatched_keys`.

Originally removed in 73e0bc692c5761e55faff39c80a26d7a3cfc748c.

src/diffusers/modeling_flax_utils.py

@@ -436,9 +436,6 @@ class FlaxModelMixin:
             )
             cls._missing_keys = missing_keys
 
-        # Mismatched keys contains tuples key/shape1/shape2 of weights in the checkpoint that have a shape not
-        # matching the weights in the model.
-        mismatched_keys = []
         for key in state.keys():
             if key in shape_state and state[key].shape != shape_state[key].shape:
                 raise ValueError(
@@ -466,26 +463,13 @@ class FlaxModelMixin:
                 f" {pretrained_model_name_or_path} and are newly initialized: {missing_keys}\nYou should probably"
                 " TRAIN this model on a down-stream task to be able to use it for predictions and inference."
             )
-        elif len(mismatched_keys) == 0:
+        else:
             logger.info(
                 f"All the weights of {model.__class__.__name__} were initialized from the model checkpoint at"
                 f" {pretrained_model_name_or_path}.\nIf your task is similar to the task the model of the checkpoint"
                 f" was trained on, you can already use {model.__class__.__name__} for predictions without further"
                 " training."
             )
-        if len(mismatched_keys) > 0:
-            mismatched_warning = "\n".join(
-                [
-                    f"- {key}: found shape {shape1} in the checkpoint and {shape2} in the model instantiated"
-                    for key, shape1, shape2 in mismatched_keys
-                ]
-            )
-            logger.warning(
-                f"Some weights of {model.__class__.__name__} were not initialized from the model checkpoint at"
-                f" {pretrained_model_name_or_path} and are newly initialized because the shapes did not"
-                f" match:\n{mismatched_warning}\nYou should probably TRAIN this model on a down-stream task to be able"
-                " to use it for predictions and inference."
-            )
 
         # dictionary of key: dtypes for the model params
         param_dtypes = jax.tree_map(lambda x: x.dtype, state)