ASoC: rsnd: add rsnd_io_to_mod()

Sometimes we would like to get each module directly, especially data path
searching. this patch adds rsnd_io_to_mod() macro, and existing
rsnd_io_to_mod_xxx() use it.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: Keita Kobayashi <keita.kobayashi.ym@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sh/rcar/rsnd.h

@@ -348,9 +348,10 @@ struct rsnd_dai_stream {
 	int byte_per_period;
 	int next_period_byte;
 };
-#define rsnd_io_to_mod_ssi(io)	((io)->mod[RSND_MOD_SSI])
-#define rsnd_io_to_mod_src(io)	((io)->mod[RSND_MOD_SRC])
-#define rsnd_io_to_mod_dvc(io)	((io)->mod[RSND_MOD_DVC])
+#define rsnd_io_to_mod(io, i)	((i) < RSND_MOD_MAX ? (io)->mod[(i)] : NULL)
+#define rsnd_io_to_mod_ssi(io)	rsnd_io_to_mod((io), RSND_MOD_SSI)
+#define rsnd_io_to_mod_src(io)	rsnd_io_to_mod((io), RSND_MOD_SRC)
+#define rsnd_io_to_mod_dvc(io)	rsnd_io_to_mod((io), RSND_MOD_DVC)
 #define rsnd_io_to_rdai(io)	((io)->rdai)
 #define rsnd_io_to_priv(io)	(rsnd_rdai_to_priv(rsnd_io_to_rdai(io)))
 #define rsnd_io_is_play(io)	(&rsnd_io_to_rdai(io)->playback == io)