t6spr: move Telephony overlay to device

These overlay settings are applicable to t6spr only, and several should
be applied to more spns than 310120. Move them out of common and into
the correct overlay structure here.

config_apn_expand was removed because it is already true by default.

Change-Id: I380e08f9508714954d31caa82d793fcca2ed99a9