overlay: add tmo and att default LTE apns

Change-Id: Ic243e0f9a37bbb50fb8d3b4c598f7e6e7e663fce
overlay: remove Verizon specific eri.xml

Restore order to the universe by removing that which is evil.

For some strange reason, Verizon devices do not agree on the eri.xml to
use, even on the same spn. Since it is not universal, it does not belong
in vendor/cm (at least while there is no automatic method to check which
eri.xml should be used). Remove these so that we don't end up with
strange double-overlay issues for devices.

Change-Id: If5a28ed03c8cc6b145c151c7ebf95fabdf81f434