move butterfly out of experimental

It's no longer experimental :-)

BRANCH=none
BUG=none
TEST=compiled and ran on butterfly (platform identified correctly)

Change-Id: Ic2f689bb935ff1d570258cc200f00e1edfd76282
Reviewed-on: https://gerrit.chromium.org/gerrit/43132
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Commit-Queue: David Hendricks <dhendrix@chromium.org>
Tested-by: David Hendricks <dhendrix@chromium.org>
14 files changed