Telephony: Add TD-SCDMA network modes

1)TD-SCDMA Signal Strength support.
2)Add TD-SCDMA network type support in MobileDataStateTracker class
to identify TD-SCDMA as UMTS variant and use the relevant
kernel data stack tcp buffer sizes defined.
3) Add TD-SCDMA to the list of supported network modes.

Change-Id: I6afd6a75b5a810a23a6a160c4adbc461d53afc3a
Merge "Telephony: Add TD-SCDMA network modes" into kitkat3