ASoC: soc-core: tidyup for snd_soc_add_card_controls()

snd_soc_add_card_controls() registers controls by using
for(... i < num; ...). If controls was NULL, num should be zero.
Thus, we don't need to check about controls pointer.
This patch also cares missing return value.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87blx1ahoi.wl-kuninori.morimoto.gx@renesas.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/soc-core.c

@@ -2058,9 +2058,10 @@ static int snd_soc_instantiate_card(struct snd_soc_card *card)
 	snd_soc_dapm_link_dai_widgets(card);
 	snd_soc_dapm_connect_dai_link_widgets(card);
 
-	if (card->controls)
-		snd_soc_add_card_controls(card, card->controls,
+	ret = snd_soc_add_card_controls(card, card->controls,
 					card->num_controls);
+	if (ret < 0)
+		goto probe_end;
 
 	ret = snd_soc_dapm_add_routes(&card->dapm, card->dapm_routes,
 				      card->num_dapm_routes);