Fix bug in Hybrid Engine
diff --git a/deepspeed/runtime/hybrid_engine.py b/deepspeed/runtime/hybrid_engine.py
index 0bddc6aeb9d4..46b1475cece9 100644
--- a/deepspeed/runtime/hybrid_engine.py
+++ b/deepspeed/runtime/hybrid_engine.py
@@ -318,7 +318,7 @@ def create_inference_module(self):
         self._orig_fwds_others = []
 
         if self._config.hybrid_engine.inference_tp_size > 1:
-            if self.mpu is not None:
+            if self.mpu is None:
                 global_rank = dist.get_rank()
                 world_size = dist.get_world_size()
                 mp_group_id = global_rank // self._config.hybrid_engine.inference_tp_size

resolves #3454

@cmikeh2 @RezaYazdaniAminabadi 