Telephony: Add TD-SCDMA network modes

1) TD-SCDMA Signal Strength support.
2) Add TD-SCDMA to the list of supported network modes.

CRs-Fixed: 403258, 479310

Conflicts:
telephony/java/android/telephony/SignalStrength.java
Change-Id: I158821574484bfaf47d1660406e591e2afb3be5e