Remove pod type references

ipu_config.json

@@ -6,7 +6,7 @@
   "executable_cache_dir": "./exe_cache",
   "gradient_accumulation_steps": 2048,
   "inference_device_iterations": 5,
-  "inference_replication_factor": {"pod4": 1, "pod8": 2, "pod16": 4, "pod32": 8, "pod64": 16, "default": 4},
+  "inference_replication_factor": 1,
   "ipus_per_replica": 4,
   "layers_per_ipu": [
     0,
@@ -20,6 +20,6 @@
   "output_mode": "final",
   "recompute_checkpoint_every_layer": true,
   "replicated_tensor_sharding": true,
-  "replication_factor": {"pod4": 1, "pod8": 2, "pod16": 4, "pod32": 8, "pod64": 16, "default": 4},
+  "replication_factor": 1,
   "seed": 42
 }