Revert "platform/chrome: chromeos_laptop: Add Leon Touch"

This reverts commit bff3c624.

Board "Leon" is otherwise known as "Toshiba CB35" and we already have
the entry that supports that board as of this commit :
963cb6fa platform/chrome: chromeos_laptop - Add Toshiba CB35 Touch

Remove this duplicate.

Signed-off-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Olof Johansson <olof@lixom.net>