Update README.md

examples/callcenter/README.md

 # Callcenter 8k sample rate
 
-Data distribution:
-
-```
-676048 utts
-491.4004722221223 h
-4357792.0 text
-2.4633630739178654 text/sec
-2.6167397877068495 sec/utt
-```
-
-train/dev/test partition:
-
-```
-    33802 manifest.dev
-    67606 manifest.test
-   574640 manifest.train
-   676048 total
-```
+This recipe only has model/data config for 8k ASR, user need to prepare data and generate manifest metafile. You can see Aishell or Libripseech.