ASoC: rsnd: add TDM Extend Mode support

Renesas R-Car can out TDM by
1) 6ch x 1 DAI as TDM Extend Mode
2) 2ch x 4 x 1 DAI as TDM split Mode
3) 2ch x 3 DAI or
   2ch x 4 DAI as TDM Multichannel Mode

This patch adds 1) TDM Extend Mode. Because of HW design,
this 6ch data will be outputed via 8ch data width.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/soc/sh/rcar/ssiu.c b/sound/soc/sh/rcar/ssiu.c
index 6120b0a..3265501 100644
--- a/sound/soc/sh/rcar/ssiu.c
+++ b/sound/soc/sh/rcar/ssiu.c
@@ -78,6 +78,15 @@
 	if (ret < 0)
 		return ret;
 
+	if (rsnd_get_slot_runtime(io) >= 6) {
+		/*
+		 * TDM Extend Mode
+		 * see
+		 *	rsnd_ssi_config_init()
+		 */
+		rsnd_mod_write(mod, SSI_MODE, 0x1);
+	}
+
 	if (rsnd_ssi_use_busif(io)) {
 		u32 val = rsnd_get_dalign(mod, io);