ASoC: rsnd: don't call update callback if it was NULL

BugLink: http://bugs.launchpad.net/bugs/1714298

commit d7289565 upstream.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Thong Ho <thong.ho.px@rvc.renesas.com>
Signed-off-by: Nhan Nguyen <nhan.nguyen.yb@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

sound/soc/sh/rcar/core.c

@@ -1016,7 +1016,7 @@ static int rsnd_kctrl_put(struct snd_kcontrol *kctrl,
 		}
 	}
 
-	if (change)
+	if (change && cfg->update)
 		cfg->update(cfg->io, mod);
 
 	return change;