Telephony: Fix DcSwitchStateMachine issues.

1. Make DDS switch working for C+G.
2. Dont indefinitely retry allow_data(True) if it fails.
3. Move to Idle state if PS is detached in ATTACHED state,
   dont aggressively retry attach.

Change-Id: I83aa5c1507e63be28265d7e7d85afc14c1dccb1c