ASoC: rcar: remove unused variable

After a recent cleanup, the soc_card variable became unused
and now produces a warning:

soc/sh/rcar/core.c: In function '__rsnd_kctrl_new':
soc/sh/rcar/core.c:801:23: warning: unused variable 'soc_card' [-Wunused-variable]

This removes the variable.

Fixes: 1a49798 ("ASoC: Change the PCM runtime array to a list")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sh/rcar/core.c

@@ -1033,7 +1033,6 @@ static int __rsnd_kctrl_new(struct rsnd_mod *mod,
 			    void (*update)(struct rsnd_dai_stream *io,
 					   struct rsnd_mod *mod))
 {
-	struct snd_soc_card *soc_card = rtd->card;
 	struct snd_card *card = rtd->card->snd_card;
 	struct snd_kcontrol *kctrl;
 	struct snd_kcontrol_new knew = {