greybus: svc: fix version response

The SVC-protocol driver currently accepts the version offered by the
SVC, but still responded with a hard-coded version.

Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>