UPSTREAM: Remove board google/panther

Once #17329 is committed, no reason to have google/panther exist
as a separate board anymore.

CQ-DEPEND=CL:414991,CL:415073
BUG=None
BRANCH=None
TEST=None

Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/17538
Reviewed-by: Martin Roth <martinroth@google.com>
Tested-by: build bot (Jenkins)

Change-Id: I9a11273c39423d5ff33a7d1f91c8d8cffef97ec1
Reviewed-on: https://chromium-review.googlesource.com/415072
Commit-Ready: Furquan Shaikh <furquan@chromium.org>
Tested-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
25 files changed