mb/google/octopus: Create fleex variant

mb/google/octopus: Create fleex variant

This creates a fleex variant for octopus. Nothing is set in the variant
files here; everything is picked up from baseboard.

BUG=b:110085182
TEST=None

Change-Id: Ia8b8bb757f67bea997b7f43489c38cac62f7682d
Signed-off-by: Justin TerAvest <teravest@chromium.org>
Reviewed-on: https://review.coreboot.org/27105
Reviewed-by: Jett Rink <jettrink@google.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>