Fix DDS switch issue for Mms on C+G

On a C+G device, when DDS is on Cdma sub, if Mms is
tried on Gsm sub, DDS switch is blocked as ps detach
on Cdma sub doesn't deactivate data call at modem.
Explicitly cleanup data call at Telephony to enable DDS
switch.

Change-Id: I6ca5c9e5073ca183e6675faf9aa14aef4443fd20