ASoC: rsnd: Add ADG reset support for RZ/G3E

RZ/G3E requires the ADG reset line to be deasserted for the audio
subsystem to operate. The ADG module clock is already managed via
rsnd_adg_clk_enable/disable() through adg->adg, so no additional
clock handling is needed.

Add support for the optional "adg" reset control on Renesas RZ/G3E SoC.

Signed-off-by: John Madieu <john.madieu.xa@bp.renesas.com>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://patch.msgid.link/20260525110230.4014435-13-john.madieu.xa@bp.renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: John Madieu

sound/soc/renesas/rcar/adg.c

@@ -771,6 +771,7 @@ void rsnd_adg_clk_dbg_info(struct rsnd_priv *priv, struct seq_file *m)
 
 int rsnd_adg_probe(struct rsnd_priv *priv)
 {
+	struct reset_control *rstc;
 	struct rsnd_adg *adg;
 	struct device *dev = rsnd_priv_to_dev(priv);
 	int ret;
@@ -779,8 +780,11 @@ int rsnd_adg_probe(struct rsnd_priv *priv)
 	if (!adg)
 		return -ENOMEM;
 
-	ret = rsnd_mod_init(priv, &adg->mod, &adg_ops,
-		      NULL, NULL, 0, 0);
+	rstc = devm_reset_control_get_optional_exclusive(dev, "adg");
+	if (IS_ERR(rstc))
+		return dev_err_probe(dev, PTR_ERR(rstc), "failed to get adg reset\n");
+
+	ret = rsnd_mod_init(priv, &adg->mod, &adg_ops, NULL, rstc, 0, 0);
 	if (ret)
 		return ret;