Remove configs for onlySingleDcAllowed

The old config value is no longer needed with the move to
CarrierConfigManager. The new configs are added to the device
overlay in vendor.xml.

Bug: 29873049
Change-Id: I5c5bd09bd9a6fe75f8a83fe690e2a8e8f1f8acfb
Merged-In: I5c5bd09bd9a6fe75f8a83fe690e2a8e8f1f8acfb
20 files changed