ASoC: rsnd: check for zero node count

Most callers of_get_child_count() check that "nr" is non-zero so it
causes a static checker warning when we don't do that here.  This
does not cause a problem or a crash, but having zero SSUIes does not
make sense either so let's add a check.

Addresses-Coverity: ("Unchecked return value")
Fixes: c413983eb6 ("ASoC: rsnd: adjust disabled module")
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210603110315.81146-1-colin.king@canonical.com
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sh/rcar/ssiu.c

@@ -515,6 +515,9 @@ int rsnd_ssiu_probe(struct rsnd_priv *priv)
 	else
 		nr = priv->ssi_nr;
 
+	if (!nr)
+		return -EINVAL;
+
 	ssiu	= devm_kcalloc(dev, nr, sizeof(*ssiu), GFP_KERNEL);
 	if (!ssiu)
 		return -ENOMEM;