remove assertion (NVIDIA#8302)

Signed-off-by: dimapihtar <dpihtar@gmail.com>
Signed-off-by: Alexandros Koumparoulis <akoumparouli@nvidia.com>

nemo/collections/nlp/models/language_modeling/megatron_gpt_model.py

@@ -1304,11 +1304,6 @@ def setup(self, stage=None):
         self.init_global_step = self.trainer.global_step
 
         if self.rampup_batch_size:
-            optimizer = self.cfg.optim.get('name', None)
-            assert (
-                optimizer == 'fused_adam'
-            ), f'{optimizer} optimizer is not supported yet with rampup batch size. Please, use fused_adam optimizer instead.'
-
             num_microbatch_calculator = apex.transformer.pipeline_parallel.utils._GLOBAL_NUM_MICROBATCHES_CALCULATOR
             num_microbatch_calculator.update(self.init_consumed_samples, consistency_check=False)
             self.prev_consumed_samples = self.init_consumed_samples