mainboard/google/slippy: remove unobtainable mainboard

The slippy board was a proof of concept device that has never
made it out in the wild. Moreover, I don't think any of these
boards exist any longer.

Change-Id: I24fb08d9be35b2367e7aa64520ce5778ab861535
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/15902
Tested-by: build bot (Jenkins)
Reviewed-by: Furquan Shaikh <furquan@google.com>

0 files changed, 0 insertions, 0 deletions