Make radio power off immediately after data cleanup is complete

Currently Telephony needs to wait 30s to make radio power off on
DDS SUB, even the data connection clean-up is finished.

To avoid the latency time, detect the progress of data cleanup on
own SUB, once it done, make radio power off immediately.

Change-Id: I0d40b027da8196397499d5f72832191fbce81ef2