Add a carrier config for WFC's carrier name override by ef_pnn

To override wifi calling's carrier name string using ef_pnn
from sim card.

Bug: 157108864
Test: UE with TMO sim card to test in Roaming and WFC on, and then
check operator name. (PASS)

Change-Id: Id72ce2a9a0fb8f45efa8a975e8052808f726a971
Merged-In: Id72ce2a9a0fb8f45efa8a975e8052808f726a971