Keep config files for old boards in platforms/

These old boards are obsolete and so their overlays were removed in
https://crrev.com/c/2223728, but we still have some useful tests that
simulate their touchpads. To keep those tests working, we just need to
keep their "X.org" configuration files around.

A couple of boards, mario and zgb, weren't being used any more, so I
just deleted those (since otherwise some tests would look for their
config files anyway when building a platform database).

BUG=none
TEST=run `touchtests`, and check that no tests error

Change-Id: I45d2b957dd3563efece02c4f150ae44cf5acee23
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/mttools/+/2264524
Reviewed-by: Jora Jacobi <jora@google.com>
Reviewed-by: Sean O'Brien <seobrien@chromium.org>
Tested-by: Harry Cutts <hcutts@chromium.org>
Commit-Queue: Harry Cutts <hcutts@chromium.org>
22 files changed