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: I158821574484bfaf47d1660406e591e2afb3be5e
CRs-Fixed: 403258, 479310
(cherry picked from commit 2ba1b7292c6b458fb72587c1f29a5c00b70717cd)
(cherry picked from commit d58b065e7e3d84461a3c981e7a7d4673f3567ef5)
(cherry picked from commit 7844d69d3d323b3969766309c2ad5bc80411fbae)