fix decoder_position_ids in decode()

vit_gpt2/modeling_flax_vit_gpt2_lm.py

@@ -289,7 +289,7 @@ class FlaxViTGPT2LMPreTrainedModel(FlaxPreTrainedModel):
                     "Make sure to provide `position_ids` when passing `past_key_values`."
                 )
 
-            position_ids = jnp.broadcast_to(
+            decoder_position_ids = jnp.broadcast_to(
                 jnp.arange(sequence_length)[None, :], (batch_size, sequence_length)
             )