Update ipu_config.json

ipu_config.json

@@ -9,9 +9,11 @@
   "replication_factor": 4,
   "gradient_accumulation_steps": 16,
   "device_iterations": 1,
+  "inference_device_iterations": 4,
+  "inference_replication_factor": 4,
   "executable_cache_dir": "./exe_cache",
 
   "ipus_per_replica": 4,
   "layers_per_ipu": [3, 7, 7, 7],
   "matmul_proportion": [0.15, 0.18, 0.20, 0.25]
-}
+}