greybus: audio_codec: Free gccodec on dia probe failure

We aren't freeing the codec, that we allocated before failing to probe
the connection. Free it.

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