ASoC: rsnd: fix ADG flags

Current ADG driver is over-writing flags. This patch fixes it.
Reported-by: NHiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

sound/soc/sh/rcar/adg.c

@@ -479,10 +479,10 @@ static void rsnd_adg_get_clkout(struct rsnd_priv *priv,
 	}
 
 	if (req_rate[0] % 48000 == 0)
-		adg->flags = AUDIO_OUT_48;
+		adg->flags |= AUDIO_OUT_48;
 
 	if (of_get_property(np, "clkout-lr-asynchronous", NULL))
-		adg->flags = LRCLK_ASYNC;
+		adg->flags |= LRCLK_ASYNC;
 
 	/*
 	 * This driver is assuming that AUDIO_CLKA/AUDIO_CLKB/AUDIO_CLKC