mosys: Remove device-tree config support

With Fizz/Coral migrations complete, this deletes legacy support for
mosys device-tree based cros_config impl.

BUG=b:119104647
TEST=emerge-coral mosys and local coral test
CQ-DEPEND=CL:1319909, CL:*709755, CL:*709786

Change-Id: I2888fe2f89ec00d64d94d4ce2dbca536961ab3ef
Reviewed-on: https://chromium-review.googlesource.com/1319970
Commit-Ready: C Shapiro <shapiroc@chromium.org>
Tested-by: C Shapiro <shapiroc@chromium.org>
Reviewed-by: Gregory Meinke <gmeinke@chromium.org>
6 files changed