Add China Telecom as LTE carrier

China Telecom offers LTE network with its USIM card, and it works on LTE-only modems.

Add configuration of the LTE network of China Telecom.

Its CDMA network is currnetly still in service (but since 2020 it starts to reject new devices sold with CDMA support).

Signed-off-by: Icenowy Zheng icenowy@aosc.io