Display the number of LTE signal bars is based on RSRP only

Some carriers require to display the number of LTE signal bars is
based on RSRP only.
This carrier config is used to control it.

Test: manual - Checked that the number of LTE signal bars display
which base on RSRP only can be controlled by carrier config.
Bug: 67831028

Change-Id: I077ef253f34fc503a591dcb3f01d60ab6573f298