Add TD-SCDMA UI support

NetworkSettings: Don't error out with TD-SCDMA values

This adds persistence and the ability to read TD-SCDMA values if
they are set. Both Network configuration and the QS tile toggle
now cycle these modes correctly
Devices supporting TD-SCDMA need to overlay the config_enabled_tdscdma
boolean configuration value to "true" for the proper network modes
to be presented to the user.

The ro.telephony.default_network should also be changed to a TD-SCDMA
value (20 or 18, depending on whether LTE is also supported)

Change-Id: I3a88a01aa9c5c111101c53388d5ba76a99cd0df6

Add TD-SCDMA UI support

Add TD-SCDMA PreferredNetwork display changes.
Add network mode TD-SCDMA to the list of
supported network modes.

PS:
- use AOSP method

Change-Id: Ib5adbf37e0fd3f17b64e64bc5b8a9d32e129af70
CRs-Fixed: 479310
(cherry picked from commit e0c7eba36ffcab551bddf9838f49278efec3f63b)
(cherry picked from commit be1bc56a5664bab05a896d8aebf808c07e946a44)
(cherry picked from commit 2275e2a28de775192675d7decbaf9d534bc312db)