greybus: module versions: remove them

We removed the module version from the spec, so remove them from the
code as well.  It's still in the manifest as we need to sync with gbsim
/ firmware when we do that, which will happen sometime in the next
weeks.

Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>