rowan: Delete board

Rowan is dead. Remove board support.

BUG=chromium:840888
TEST=None
BRANCH=None
CQ-DEPEND=CL:*1087044,CL:1538915

Change-Id: Ia87f5ad9829dead4a06ccb468d6a4a9cddb54ad2
Signed-off-by: Evan Green <evgreen@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1540439
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
3 files changed